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2014 BAE Abstracts

Enhanced Land Treatment Of Food Processing Wastewaters

Authors: Niroj Aryal; Dawn Reinhold

Abstract: Land application of high-strength food processing wastewater can result in anoxic and anaerobic soil environments. Under these conditions, metals like manganese, iron, and arsenic can leach, pollute ground water, a major source of drinking water. On the other hand, nitrate pollution may occur under aerobic conditions due to nitrification of ammonium and organic nitrogen. Poplar plantations could reduce both metals and nitrate problems while allowing increased rates of land application of food processing wastewater. This experiment used field and column studies to identify underlying processes that contribute to the potential of poplar trees to reduce metal and nitrate leaching.

Results show that poplar tree growth is not hindered by application of wastewater at the rate of 1-2 times highest current application rate in Michigan. Poplar plants significantly removed more water from soils than evaporation alone with a crop factor of 3.86 ±0.6, indicating decreased soil moisture, decreased reducing conditions in soil, and increased allowable rates of wastewater application would be expected for poplar plantations (as compared to existing land application sites). Carbon treatment was enhanced by poplar trees likely due to rhizostimulation. While microbial and soil redox data is under analysis, initial results in metal mobilization showed that metal (including arsenic) concentrations in stems and leaves of trees irrigated with food processing wastewater were significantly greater than that in trees irrigated with waters. Consequently, poplar trees demonstrate great potential for enhanced land treatment of wastewaters.

 This work was supported in part by Michigan Department of Agriculture and Rural Development, Project GREEEN


Effect Of Saturation On Nutrient Removal And Drought Resilience In Stormwater Treatment Systems

Authors: Rebecca Bender; Dawn Reinhold

Abstract: Constructed wetlands and bioretention systems are widely accepted as stormwater best management practices. These systems are designed to retain water and reduce the effects of nonpoint pollution through retention and remediation with infiltration, filtration, sorption, and biological activity. However, the optimal water content for pollutant removal has yet to be identified in a quantifiable manner. Likewise, the resilience of these ecological systems to drought and their recovery time to maximum performance should be studied methodically. In controlled columns and in five field-scale systems, parallel systems of varying water content will be evaluated for stormwater treatment performance (including removal of sediment, total phosphorus, total nitrogen, nitrates, nitrite, ammonia and pH change). Ecological resilience will be monitored in regards to plant health and insect diversity. Once established, the systems will undergo a drought simulation and then a monitored recovery period until remediation performance is reestablished. Similar vegetation, soil composition, and pollutant loading will isolate the effect of saturation on system performance and contribute to knowledge of system design and management. Such qualitative and quantitative analysis is an important part of justifying and promoting use of wetlands and bioretention for stormwater best management.


Optimization Of A Torrefied Pellet Plant To Reduce Production And Supply Costs

Authors: Li Chai; Christopher M. Saffron

Abstract: Torrefaction is a preprocessing technology that upgrades biomass to a form with improved physical and chemical properties. In torrefaction, heat is added in the absence of oxygen to perform a mild pyrolysis of the structural components of biomass. The advantages of torrefied biomass versus untreated biomass include: 1) reduced transportation costs due to densification, 2) improved storage stability due to increased hydrophobicity, and 3) reduced grinding costs due to increased friability. Because of these benefits, torrefaction is being considered to produce a drop-in replacement for coal. Decentralized torrefaction involves the regional deployment of relatively small facilities near the area of biomass harvest. A trade-off exists between economies of scale and economies of transportation. Smaller scales benefit transportation but more capital investment is needed to process a given amount of biomass. Small scales are also prone to higher risks due to issues with biomass storage. A technoeconomic model was formulated to examine the costs and benefits of decentralized torrefaction systems. The optimum plant capacity was determined using economic metrics as objective functions.


Evaluating Environmental Justice Model Performances At Different Census Levels

Authors: Fariborz Daneshvar; A. Pouyan Nejadhashemi; Zhen Zhang; Georgina M. Sanchez; Geoffrey Habron; Sandra Marquart-Pyatt; Ashton Shortridge; Matthew R. Herman

Abstract: This study considers both stream health and socio-economic data to develop a predictive model for water quality by using socio-economic data variation. The Saginaw River watershed, which is the biggest six digit Hydrologic Unit Code watershed in Michigan, was selected as the study area. Socio-economic data from 2010 US census was collected at three levels (county, census tract, and block group) for the study area and four stream health indicators including the Index of Biological Integrity (IBI), Hilsenhoff Biotic Index (HBI), Family IBI, and total number of Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa, were used to evaluate stream health condition. The Conditional Autoregressive (CAR) model was used to predict stream health indicators using sixteen socio-economic parameters at three resolutions while considering multi-level interaction. Results obtained from the block group level analysis, were significantly different from the county level. Therefore, socio-economic and eco-environment model developed with county level resolution can be misleading. In general, spatial dependence needs to be considered for a model development, especially at fine scales. Finally based on the results obtained from this study, multilevel interactions will further improve model prediction accuracy.


The Effectiveness Of AGIS Process On Fats, Oil And Grease Using A Septic Drain Field

Authors: Younsuk Dong; Steven Safferman

Abstract: Fats, oil, and grease (FOG) are in animal meat, cooking oil and dairy products. When FOG is discharged to sewers, it builds up over time and clogs the sewer pipes. Blocked pipes can create overflows and backups that cause odor and the surfacing of untreated wastewater. Sustainable Environmental Technologies, Inc., (SET) developed the Advanced Grease Interceptor System (AGIS) to manage FOG. The AGIS uses aeration equipment, baffles and a one-time inoculum in a standard septic tank to microbiologically partially breakdown FOG. The remaining FOG easily flows through the sewer without causing clogging. The effect of the decomposed FOG in a drain field is not understood and is being evaluated in this research. To investigate, simulated drain fields were constructed with moisture sensors to detect the progress a flow through the soil. Five different conditions are being tested including representative wastewater samples with and a without AGIS treatment to determine clogging potential. In addition, the research will measure the triglyceride components before and after treatment with the AGIS. FOGs are composed of triglycerides, which are formed by 3-fatty acid bound to an ester composed of a glycerol. Many triglycerides have a characteristic of stickiness which results in sewer pipe clogging. In order to test triglyceride, solid phase extraction of FOG within the wastewater is the first step, followed by high performance liquid chromatography (HPLC) to identify each component.

This work was supported in part by Sustainable Environmental Technologies; Michigan Corporate Relations Network; MSU Bioeconomy Institute i6 Green Proof of Concept Center


Data Management Practices For Low And Negative Plate Counts Affect The Confidence Intervals Of The Estimated Parameters Of Microbial Reduction Models

Authors: Francisco Garcés-Vega; Bradley Marks

Abstract: Experimental limits of detection (LOD) affect data for developing microbial reduction models. To deal with this, published approaches include: considering only positive values (Y+), or replacing negative results by: the LOD, one half the LOD, one divided by the LOD, or a random number between 0 and the LOD. Recent results show that these practices significantly affect accuracy of estimated parameters.

Our objective was to quantify the effect of data management practices on confidence interval sizes (CIS) for resulting model parameters.

Simulated microbial reduction data sets (n=100), were synthesized (YOBS). The low-count data management practices described above were applied. Log-linear and Weibull models were fit to the resulting data sets. The CIS of the parameters were estimated, and then compared by ANOVA and Tukey.

The ranking of CIS among data management practices varied among data and model types. The Y+ approach, previously shown to be the most accurate, often had the largest CIS, as double (P<0.05) those for YOBS. For the other approaches, the CIS fell between those of YOBS and Y+; 22 out of 30 cases yielded CIS greater (P<0.05) than those for YOBS.

These suggest that the application of low-count data management practices affects the accuracy and uncertainty of the model parameters. The fact that the CIS of Y+ were most often the largest indicated that predictions based on these results, even if more accurate, are also more uncertain. This could influence model selection and utility in risk assessments and food safety management.

This work was supported in part by Colciencias-Fulbright scholarship (2012)


Biomass Fast Pyrolysis And Electrocatalysis For Liquid Fuel Production And Value Addition

Authors: Mahlet Garedew; Zhenglong Li; Chun Ho Lam; James E. Jackson; Christopher M. Saffron

Abstract: The production of liquid hydrocarbon fuels from biomass is needed to replace fossil fuels, which are decreasing in supply at an unsustainable rate. Renewable fuels also address the rising levels of greenhouse gases, an issue for which the Intergovernmental Panel on Climate Change implicated humanity in 2013. In response, the Energy Independence and Security Act (EISA) mandates the production of 21 billion gallons of advanced biofuels by 2022. Biomass fast pyrolysis (BFP) uses heat (400-600°C) without oxygen to convert biomass to fuels offering an alternative to fossil fuels and a means to meet the EISA mandate. The major product, bio-oil, can be further upgraded to liquid hydrocarbon fuels, while biochar can serve as a solid fuel or soil amendment. The combustible gas co-product is typically burned for process heat. Though the most valuable of the pyrolysis products, bio-oil is highly oxygenated, corrosive, low in energy content and unstable during storage. As a means of improving bio-oil properties, electrocatalytic hydrogenation (ECH) is employed to reduce and deoxygenate reactive compounds. In this study, model compounds representative of bio-oil components are subjected to ECH under mild conditions using ruthenium on activated carbon (Ru/ACC) as a catalytic cathode. To date, model monomers (guaiacol, syringol and phenol) and model dimers (4-pehnoxyphenol) have successfully been reduced using this method. Further work in this area focuses on pyrolysis and electrocatalysis of lignin. As lignin comprises up to 30% of the mass and 40% of the energy stored in biomass it offers great potential as feedstock for BFP.

This work was supported in part by Great Lakes Bioenergy Research Center


Evaluation Of Feedstocks For Achieving Michigan State University’s Energy Transition Plan Goals With Torrefied Biomass

Authors: Kristen Henn; Christopher M. Saffron; Raymond O. Miller; Richard E. Baker

Abstract: Michigan State University’s Energy Transition Plan (ETP) sets a goal of 15% renewable energy production by 2015. Anaerobic digestion, wind, solar power and alternative fuels currently contribute to 8% of the total energy portfolio. The T.B. Simon Power Plant also combusts raw biomass accounting for a small portion of the 8%. Another electric power source is required to meet the ETP goal. Raw biomass is not desirable for efficient combustion due to high moisture content, low energy density and poor grindability. However, biomass can be thermally upgraded by torrefaction; a process that converts biomass into a product that is a drop-in coal replacement. During torrefaction, the properties of biomass are upgraded to form an energy dense, friable, hydrophobic, biologically stable and easily combustible solid fuel.

Historically, electricity production from torrefied biomass has a higher cost than coal or natural gas. Therefore, selecting feedstocks that can readily be converted to “drop-in” form is necessary to reduce costs. While the effects of torrefaction operating conditions have been extensively studied, the dependence of torrefied biomass properties on raw biomass composition is not well understood. Closing this knowledge gap requires connecting feedstock and product properties using advanced multivariate analysis (MVA). The observations generated by MVA will be used to understand the mechanisms of biomass conversion during torrefaction. The dependence of torrefied biomass properties on feedstock composition will be discussed.


A Review Of Macroinvertebrate And Fish Stream Health Indices

Authors: Matthew Herman; A. Pouyan Nejadhashemi

Abstract: The focus of this review is to discuss the current use and development of macroinvertebrate and fish indicators for stream health. Macroinvertebrates and fish are commonly used indicators of stream heath, due to their ability to represent degradation occurring within local regions (macroinvertebrates) and within the entire river system (fish). The next section of the review discusses several types of common components, or metrics, used in the creation of indices. Following this discussion of common metrics, the review will focus on the different methods used for macroinvertebrate and fish collection, in both wadeable and non-wadeable aquatic ecosystems. With the basics of macroinvertebrate and fish indices discussed, emphasis will be placed on the application of indices and the different regions for which they are developed. The final section will do a brief summary of the benefits and limitations of macroinvertebrate and fish indices.


Impact Of Inoculation Procedures On Thermal Resistance Of Salmonella In Wheat Flour And Associated Repeatability Of Results

Authors: Ian Hildebrandt; Bradley Marks; Elliot Ryser; Rossana Villa-Rojas; Juming Tang; Sarah Buchholz

Abstract: Investigation of Salmonella inactivation involves artificial inoculation of a food matrix. However, most studies focus on the effects of the treatment variable, neglecting to consider the influence of inoculation procedures. The objective was to quantify the impact of inoculation methodology on thermal resistance of Salmonella in wheat flour, and repeatability in a two-laboratory comparison study. Batches of wheat flour (100 g) were inoculated with Salmonella by five methods: (A) high-concentration, low-liquid volume (HCLV) broth, (B) HCLV suspended lawn, (C) pelleted and resuspended lawn, (D) direct contact with a lawn, and (E) fomite transfer of a lawn. Afterwards, samples were equilibrated to ~0.45 aw in a controlled-humidity chamber, subjected to isothermal (80°C) treatments in aluminum cells in a water bath, immediately cooled, diluted, plated, and enumerated. D-values were computed from the resulting log CFU/g data by linear regression. Post-equilibration and post-come-up Salmonella populations ranged from 8.7 to 6.3 and 7.7 to 3.7 log CFU/g, respectively. Method A yielded the largest population decline during equilibration (~3 log) and come-up (~2.5 log), and the highest D-value (504.9 s), compared to the other methods (P < 0.05). The MSU-generated D-values for methods B, C, and D were clustered (250.9, 285.9, and 226.7 s, respectively), but were statistically different. Based on these findings, careful consideration should be given to the inoculation method, which can significantly impact thermal resistance of Salmonella in low-moisture foods, and the uncertainty, which can significantly affect utility of models.

This work was supported in part by USDA - NIFSI


Correlating Maize Cell Wall Properties To Their Response To Alkaline Pretreatment And Enzymatic Hydrolysis

Authors: Muyang Li; Dan Williams; David Hodge

Abstract: Maize (Zea mays L.) stover has the largest production area in the United States as a bioenergy feedstock. The environmental and agronomic factors such as maturity, nutrients and genetics may impact the maize cell wall properties, which results in differences in pretreatability, ruminant digestibility, and cellulolytic enzyme hydrolyzability. Alkaline treatments, which are well-suited to the monocot grasses, have been utilized in this study to test the response between diverse maize towards alkali pretreatment. The cell wall composition and hydrophobicity of the lignified grasses cell wall have been altered by alkaline pretreatment and those properties are related with the enhanced enzymatic digestibility. In this study, water retention value (WRV) representing porosity and hydrophilicity and the other grasses cell wall properties including lignin, xylan and p-hydroxylcinnamic acids, were determined for a maize diversity set containing 27 maize lines. The correlation between these cell wall properties have been cluster analyzed, and their contributions to the enzymatic hydrolysis yield have been compared by multivariate modeling. Additionally, high-throughput analysis techniques including pyrolysis molecular beam mass spectrometry (py-MBMS) was utilized in combination with chemometric models to both predict the cell wall properties including lignin content, p-coumaric and ferulic acids content, and hydrolysis yields.

This work was supported in part by This study was financially supported by Department of Energy through GLBRC project: BER DE-FC02-07ER64494


Effect Of Product Structure On Thermal Resistance Of Salmonella Enteritidis PT30 On Whole Almonds, In Almond Meal And In Almond Butter

Authors: Pichamon Limcharoenchat; Bradley P. Marks; Ian Hildebrandt; Nicole Hall

Abstract: Almonds can be contaminated with Salmonella in the production environment. Subsequent valued-added processes change product structure, but the impact on pathogen thermal resistance has not been reported. The objective was to quantify the effect of product structure on thermal resistance of Salmonella Enteritidis PT30 inoculated onto whole almonds subsequently ground into meal and butter.

Almonds were inoculated with Salmonella Enteritidis PT30 (~10^8 CFU/g) and equilibrated to ~0.4 aw. After equilibration, almonds were ground in a food processor (45 s) to produce almond meal sized between U.S. standard sieves #20 and 80. Almond butter was produced by further milling almonds for 15 min, with dry ice added. All products were re-equilibrated. Inoculated almonds were individually vacuum-packed in thin layer plastic bags, and meal and butter samples were packed in aluminum test cells. Samples were heated in an isothermal water bath (~80°C), with almonds pulled every 10 min for 1 h, and others pulled every 15 min for 2.5 h; all were cooled immediately in an ice bath, diluted in peptone water, and plated on mTSA to enumerate survivors.

Initial Salmonella populations and sample water activities were not significantly different (P>0.05) after grinding and milling. However, D80°C values, determined by linear regression of the survivor curves, were greater (P<0.05) in almond meal (58.8 min) and almond butter (62.9 min) than on the whole almonds (17.9 min).

Changing the product structure significantly impacted Salmonella thermal resistance. Therefore, it is extremely important to use product-specific inactivation parameters when validating pasteurization processes.

This work was supported in part by The U.S. Department of Agriculture, National Institute of Food and Agriculture, Award No. 2011-51110-30994.


Reclamation Of Anaerobic Digestion Effluent Via Electrocoagulation And Algal Culture

Authors: Zhiguo Liu; Dave Stromberg; Wei Liao; Yan (Susie) Liu

Abstract: Anaerobic Digestion (AD) is practical and efficient in utilizing various organic wastes, such as animal manure, municipal sludge, and food wastes, for production of biogas - an important energy alternative. However, liquid effluent from AD (Liquid AD effluent) remains high in biological oxygen demand (BOD), chemical oxygen demand (COD), as well as unpleasant smell and other nutrients (nitrogen and phosphorus). Appropriate treatments of liquid AD effluent are thus needed. To address this need, a multiple-stage AD effluent treatment and utilization process was developed to simultaneously reclaim the water from liquid digestate, and generate value-added algal biomass. The system starts with an optimization of electrocoagulation (EC) process, in regards of mass nutrients removal and turbidity improvement. An algal cultivation unit was then carried out using the EC effluent with significantly improved clarity to strengthen TN removal performance and accumulate algal biomass. This study integrated water reclamation from AD effluent, and algae cultivation to systematically address challenges of anaerobic digestion technology and advance its industrial applications.

This work was supported in part by DQY Agriculture Technology CO, LTD, China


 Effects Of Physical Variables On Salmonella Transfer From Produce To Stainless Steel

Authors: Beatriz Mazón; Bradley Marks; Lin Ren; Elliot Ryser

Abstract: Prior work has suggested that bacterial transfer from produce to contact surfaces during slicing is affected by surface roughness, relative contact speed, distance, and normal force. However, mathematical models of these relationships have not been well developed, as prior studies typically tested overall transfer results, but did not elucidate single-variable effects.

The objective was to quantify the effect of four physical variables on Salmonella transfer to stainless steel during sliding contact with potatoes used as the model product.

Peeled potatoes were cut into 3-cm cubes, spot-inoculated with Salmonella Typhimirium LT2 (~6 log CFU/cm2), and then pulled (using a controlled speed-force machine) across a 304 stainless steel plate with variations in surface roughness (brushed vs. mirror finish), sliding speed (2, 5, 8 mm/s), total contact distance (20, 30, 180 cm), and additional mass placed on the product (30, 60, 90 g) to obtain different normal forces. After contact, Kimwipe® samples collected from the potato/stainless steel contact path were appropriately diluted and plated on modified trypticase soy agar to quantify Salmonella. Bacterial populations along the contact path were analyzed via a repeated measures statistical analysis.

Greater transfer (P < 0.05) was seen to mirror-finished stainless steel. Overall, normal force did not significantly affect transfer, except at long contact distances; however, contact speed and distance impacted cumulative transfer (P < 0.05) for certain cases. For example, greater cumulative transfer (P < 0.05) occurred over 30 cm of contact at 5 mm/s than at 2 mm/s (420,000 vs. 190,000 CFU total).

Quantifying the effects of individual physical variables is critical to the future development of bacterial transfer models and the refabricating/redesigning of fresh-cut processing equipment and related produce-handling operations to minimize cross-contamination.


Saliva Viscosity Influence On Acid Uptake In Rice Boluses

Authors: Yamile Mennah; Gail Bornhorst

Abstract: The rheological properties of saliva show large variation between individuals due to several factors such as age, dental status and type of food consumed. Differences in saliva viscosity may have an impact on food digestion when the food reaches the stomach, reducing mass transport of gastric acid into the bolus. The objective of this study was to determine the uptake of acid into rice boluses formed with saliva of varying viscosity. Simulated saliva viscosity was modified using guar gum (0%, 0.5% and 1%) and was mixed with white medium grain rice during a simulated mastication step. The bolus was introduced into a plastic syringe with one side opened and the other sealed, and incubated in simulated gastric juice at 37°C. Bolus acidity was measured by titration after 2 to 60 hours of incubation (6 time points). Acidity values for boluses with 0% 0.5%, 1% guar gum were 0.18±06, 0.27±0.09, and 0.31±0.09 mg HCl/g dry matter after 2 hours, respectively. After 60 hours, boluses made with saliva with 0%, 0.5% and 1% guar gum had an acidity of 5.17±0.54, 5.37±0.27, 4.95±0.27 mg HCl/g dry matter, respectively. The overall acidity was significantly influenced by time (p < 0.0001), and the time x guar gum interaction (p = 0.0015). The level of guar gum did not significantly influence the overall acidity (p<0.0842). Although saliva viscosity did not significantly influence mass transport of gastric acid, future studies need to be done to determine the role of gastric juice viscosity during digestion.


Recovery of Bacillus anthracis Spores Drom HVAC Filters Using Two Quantification Techniques

Authors: Bharathi Murali; Jade Mitchell;

Abstract: Understanding the ability of microorganisms to adhere on fomite surfaces is an important component in modeling their recovery and ultimately the risk they pose.  For example B. anthracis, the endospore forming Category A biothreat agent that is frequently found in nature, can pose a high biological threat in indoor air and on surfaces. The spores have been found to be extremely resistant to environmental stresses, and are stable over decades. Microbial recovery of spores from HVAC filters, an example of a porous fomite media, which can capture a significant quantity of microorganisms when there is an attack of bioterrorism, is investigated. Since these filters have been found to become distribution conduits in the entire building, in the event of a bio-attack, experimental studies can help identify appropriate recovery factors which may subsequently inform studies on persistence. This study specifically investigates the recovery of B. anthracis over time with culture-based and molecular-based quantification techniques.  Twofold quantification was found to be significant when considering recovery efficiency to distinguish between the live and dead counts. Further research on the recovery of Bacillus spores could explain the differences in factors that affect adhesion on porous surfaces. Our analysis demonstrates the importance of understanding the variability in recovery over time and the selection of quantification methods for studies measuring persistence. Keywords: Bacillus anthracis, anthrax, biothreat agents, microbial recovery

This work was supported in part by Partially funded by the Center for Advancing Microbial Risk Assessment (a jointly funded Center of Excellence by the U.S. EPA and the Department of Homeland Security)


Climate-Smart Agriculture For Enhanced Food Security

Authors: Melissa Rojas-Downing; A. Pouyan Nejadhashemi

Abstract: There is a need to increase agricultural production by 70 percent by 2050 due to projections of population growth. In addition, rapid urbanization threatens the existing agricultural lands. Meanwhile, several estimates indicate that climate change could significantly reduce agriculture production, especially in the most food insecure regions of the world. Therefore, there is need to increase agricultural production on less land and under less reliable and harsher climatological conditions. In addition, in order to promote sustainable agriculture and food production there is a need to use less energy, fertilizer, and pesticide without invading the most sensitive ecosystems and protecting water quality. In 2009 the Food and Agriculture Organization defined “Climate Smart Agriculture” as “agriculture that sustainably increases productivity, resilience, reduces or removes Greenhouse Gases, and enhances achievement of national food security and development goals”. The goal of this study was to evaluate the existing methods and technologies for producing more food on less land, using less water, energy, fertilizer and pesticides while protecting the environment. Comprehensive literature-review was perfumed in different area of concerns including land management, integrated nutrient management, pest control, water conservation, and energy use efficiency. Each practice was evaluated based on productivity impacts, climate adaptation benefits and greenhouse gas emissions mitigation criteria. Overall the performance of different techniques varies on different regions. Under application of the most sustainable techniques, dry areas present more resilience and humid areas show higher mitigation potential to climate change, while the impacts on yield will vary by adopted techniques.


 Microbial Lipid Production From Combined Corn Stover Hydrolysate By Oleaginous Fungus For Advanced Biofuel Production

Authors: Zhenhua Ruan; Michael Zanotti; Wei Liao; Yan Liu

Abstract: A combined hydrolysis process, which first mixed dilute acid- and alkali-pretreated corn stover at a 1:1 (w/w) ratio, directly followed by enzymatic saccharification without pH adjustment, has been developed in this study in order to remove steps of neutralization, detoxification, and washing during the process of lignocellulosic biofuel production. The oleaginous fungus M. isabellina was selected and applied to the combined hydrolysate as well as a synthetic medium to compare fungal lipid accumulation. Fungal cultivation on combined hydrolysate exhibited comparable cell mass and lipid yields with those from synthetic medium, indicating that the integration of combined hydrolysis with oleaginous fungal lipid fermentation has great potential to improve performance of advanced lignocellulosic biofuel production.


Effect Of Rapid Desiccation On Thermal Resistance Of Salmonella In Wheat Flour

Authors: Danielle Smith; Bradley P. Marks

Abstract: Salmonella is able to survive in low moisture environments, and has been shown to become more resistant to heat as the water activity (aw) of the product decreases. However, it is unknown how rapidly the resistance changes if the product water activity is rapidly altered. Wheat flour was inoculated with Salmonella Enteritidis PT30 then divided into three treatment groups. Groups A and B were equilibrated over ~4 d in controlled-humidity chambers to 0.6 and 0.3 aw, respectively. Group C was equilibrated to 0.6 aw, then rapidly dried to 0.3 aw (< 4 min), using desiccated room temperature air in a small fluidized bed drying system. Samples then immediately (within ~1 min) were isothermally treated (80°C) in aluminum test cells, immediately cooled in ice water, serially diluted, and plated on modified trypticase soy agar with yeast extract for enumeration of survivors. D-values were calculated and compared via ANOVA. The rapidly desiccated group (C) and the group initially equilibrated to 0.3 water activity (B) were not significantly different (P > 0.05), but both were significantly greater than for the group initially equilibrated to 0.6 water activity (P < 0.05). Salmonella in the rapidly desiccated flour (0.3 aw) was as thermally resistant as that which previously had been equilibrated to 0.3 aw. These results suggest that the observed enhanced thermal resistance of Salmonella at lower aw is a state function that requires negligible adaption time.

This work was supported in part by USDA-NIFSI


Impacts Of Climate Change On Stream Ecosystem Integrity

Authors: Sean A. Woznicki; A. Pouyan Nejadhashemi; Yaseen Hamaamin

Abstract: Anthropogenically-driven climate change is projected to alter water resources and aquatic ecosystems. Changes in the hydrological behavior of streams and increased magnitudes of nonpoint source pollution concentrations negatively impact ecological components of streams, such as fish and macroinvertebrates. While it is important to understand the consequences of climate change on aquatic ecosystem health, it is imperative to identify the quantitative risk of these consequences. By recognizing the risk of adverse impacts to aquatic ecosystem health locally and regionally, adaptation strategies can be prioritized. This study quantifies the potential impacts of changing climate on aquatic ecosystem integrity by coupling climate models, a watershed/water quality model, and ecological models. Statistically downscaled daily climate data from ten coupled atmosphere-ocean general circulation models (AOGCMs) driven by four IPCC SRES storylines (A1F1, A1B, A2, and B1) are used with a high-resolution Soil and Water Assessment Tool (SWAT) to develop information on projected future hydrology and water quality for the River Raisin Watershed in Mchigan. In-stream hydrological and water quality data were then used to predict fish and macroinvertebrate measures of stream health based on biological sampling data. Ecological model development was performed using adaptive neuro-fuzzy inference systems (ANFIS). Best models were selected by prediction of stream health measures at biological sampling locations and extended to all streams in the watershed. Through the use of several AOGCMs, emissions scenarios, and stream health measures, we develop multiple projections for the risk of deteriorating aquatic ecosystem integrity due to climate change at local stream and watershed scales.


A Self-Sustaining Advanced Lignocellulosic Biofuel Production By Integration Of Anaerobic Digestion And Aerobic Fungal Fermentation

Authors: Yuan Zhong; Zhenhua Ruan; Steven Archer; Yingkui Zhong; Yan Liu; Wei Liao

Abstract: Microbial biodiesel production from lignocellulosic materials has gained intensive attention in recent years. However, the high energy input, particularly during the aerobic fungal fermentation stage, is hindering the development and application of the technology. Renewable energy sources from organic wastes could be a good solution to satisfy the energy demand and sustain the microbial biodiesel production. Anaerobic digestion (AD), a biological conversion process to convert organic residues into renewable energy, was applied in this study to convert organic wastes into bioenergy to power microbial biodiesel production. Besides providing the required energy, anaerobically digested fiber (AD fiber), a major output stream in AD process, has been proven to be a promising feedstock to be mixed with other lignocellulosic materials for biodiesel production.

In this study, corn stover, dairy manure, and food wastes were used as feedstocks for both anaerobic digestion and aerobic fungal fermentation to sustainably produce biodiesel. Dairy manure and food waste were anaerobically digested to produce energy and AD fiber. AD fiber and corn stover were then processed by a combined alkali and acid hydrolysis followed by a fungal fermentation to produce biodiesel. Based on the experimental results, a comprehensive mass and energy balance was also conducted and a self-sustaining lignocellulosic biodiesel production process was concluded.

This work was supported in part by Strategic Environmental Research and Development Program (SERDP), United States Department of Defense