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Scientific Contribution: 

During fifteen years of my research career, I have worked on several projects for bioprocess development using the low-cost materials or waste from domestic and local industries. The major objective was to produce value-added products from these materials along with effective waste management. The focus was always to explore innovative ideas towards process development and integrate existing advanced technology for its best performance. The technology explored for the process were mainly microbial enzyme technology (aerobic fermentation), anaerobic digestion and dark fermentations in batch, fed-batch as well as in continuous production modes.

Currently, I am working as Research Assistant Professor at Korea University and with major aim of waste management and energy production. My latest focus is to economize algal-bioprocess by improving mixotrophic reactor design, cultivation strategies via enhanced biomass/lipid yields from industrial wastes for cost-effective biodiesel.

In the followings projects/research objectives I have been worked and successfully completed:  

(1) Molecular cloning, overexpression and biochemical characterization of β-lactamases gene of Mycobacterium tuberculosis H37Rv;

(2) Siderophoregenic probiotic development for iron nutrition in animal and human;

(3) Bioadhesive development for structural application in metal and wood adherends;

(4) Extraction of extracellular and intracellular carbohydrates from marine algae Porphyridium cruentum and their biochemical characterization for industrial applications (Algorefinery).

(5) Biohydrogen production from agro-waste and separation of VFA using membrane technology

(6) Industrial biohydrogen and biomethane (biohythane) production from agro/industrial waste.

(7) Development of a strategy to improve yield of biohydrogen production by organic acid supplementation

(8) Nutrient capturing from waste using biochar and application of resulting biochar for plant growth promotion.

(9) Industrial biomethane production from co-digestion of food waste and sewage sludge from prototype sewage sludge reactors to establish the strategy of effective food waste management.

(10) Mixotrophic microalgae cultivation to improve biomass/lipid production and develop algae based waste treatment platform as cost-effective and sustainable bioprocess

Scientific Contributions (process details):

(1) Investigation and confirmation of two hypothetical β-lactamases other than Class A in the degradation of beta lactam ring against tuberculosis drugs. Such finding would help in the development of new and effective drug regime considering the involvement of other two β-lactamases which was not referred during previous TB drug designing (found in current studies).

I worked on hypothetical mycobacterium β-lactamases production and their biochemical characterization. During the course of studies, we were successful in isolating and cloning various β-lactamases genes from Mycobacterium tuberculosis H37Rv in E coli strains and their over-expressions. From this study, we could prove that there were two other genes involved for multi-drug resistance of pathogen against different classes of beta-lactam antibiotics, which were not reported before. This work helped to gain great expertise in molecular biology.

(2) Development of new siderophoregenic probiotic strains which shows the ability to scavenge insoluble iron in the GUT found in daily diet and make them bioavailable and help in iron nutrition in animal and humans.

During my doctoral studies at School of Life Sciences, North Maharashtra University, Jalgaon India, I have worked for the development of new siderophoregenic probiotics which have shown ability to scavenge insoluble iron in the GUT condition available in daily diets and make them bio-available consequently helps in iron nutrition in animal and humans. Moreover, I have explored other siderophoregenic microbial strains (non-probiotics) for siderophore production in submerged fermentation for promotion of PGPR in wheat plant. This study aimed to increase the iron content in wheat grains. The laboratory results of this study were further evaluated in pot trial in automated greenhouse conditions as well as in field conditions. In vitro studies on the probiotics suggested that these could be highly useful candidates for numerous health benefits, especially for iron nutrition.

(3) Investigation of unique plasticizers blending in chitosan bioadhesive development to enhance its mechanical strength for structural application in wood and metal adherends.

We have investigated unique plasticizers which improved the structural adhesion property of chitosan bioadhesive after formulation in appropriate ratio. From examined three plasticizers, 1% glycerol blending improved best bonding strength via three H bonds with of chitosan employing -OH groups. I have reported bonding with high structural shear strength up to 6 MPa on wood and more than 25 MPa peak shear strength on aluminum adherends. These bioadhesive found to be cost effective and offering impressive structure application which would help to replace environmental and health hazardous chemical based adhesive for general application and encourage green bioadhesive. Two patents (for investigating unique plasticizers for improved bonding) and couples of publications were obtained from above work. 

(4) Developed an effective fractionation (various sizes), and separation process of microalgal exopolysaccharides (from sea salts) by using membrane technology based on their molecular sizes.

I also worked on algo-refinery project, which had its final aim to optimizing extraction process parameters for valorization of polysaccharides from Porphyridium cruentum. This involved studies on the purification and fractionation of polysaccharides using conventional (solvent extraction and dialysis) method and advanced method using membrane technology. Microalgal EPS has been effectively separated from salt fraction using 300 kDA cut off membrane through diafiltration technique and ensure purity of EPS in large scale process. From this study we reported 1.4g/L Glc Eq concentration of broth was best (0.6 g/L dilution) which helped to avoid critical overlap interaction for effective separation. At ^DP equal to 2 bar and PTM 1 bar, 98% salt were removed in 100 min using 12L of diavolume which was one of the best report for large scale EPS separation process.

(5) Effective separation of VFA from fermenting broth using membrane technology (external-internal membrane bioreactor with hollow fibre membrane) from continuous system.  During my post-doctoral studies at Institute Pascal, UMR, CNRS, University of Blaise Pascal, France, I was involved in a major integrated BAMI project on biohydrogen production using VFA platform from anaerobic digestion of agro-waste. Our main aim was to achieve online continuous separation of VFA from fermenting broth using membrane technology (external-internal membrane bioreactor with hollow fibre membrane) to facilitate continuous dark fermentation without building up VFA. C5 stream of lignocellulosic biomass was used using HF membrane (external-internal) system and for biomethane production.

(6) Development of cost-effective bioprocess for production of industrial biohydrogen from unutilized C5 sugar stream of pretreated lignocellulosic biomasses and biomethane from ethanol plant wastes (biomass extractive), It would help to remove the economic constraint of the overall bioethanol process by its onsite applications and also offer waste management.

During my work at Indian Oil Corp Ltd, R&D Centre, Faridabad, I was involved in the development of economically viable lignocellulosic bioethanol technology with a group dedicatedly working to develop a feasible ethanol technology for the nation using lignocellulosic waste. Our aim was to establish 10-ton plant capacity per day. Our group collaborated with ICT, Mumbai group to bring the bioethanol technology via enzymatic route and successfully demonstrated the process at IGL, Kashipur. We have focused on multi-feed (wheat straw, rice straw, cotton stalk, sugarcane tops etc) and opted for dilute acid pre-treatment using screw feeder and steam explosion reactors. We have pilot plant pre-treatment facility installed in collaboration with NREL, USA. Our group also focused on production and scale-up of in-house cellulases with 150L CSTR fermenter for cellulase production. My main role in the group was to decrease economic constrains of cellulosic ethanol process by utilizing low values or waste fractions of the process such as washing fraction of biomass as extractives (before pretreatment), post distillation and cellulase fermentative slurry etc. Also, conversion of C5 sugar stream of pretreated lignocellulosic biomasses into biohydrogen which was achieved with approx. 2.6 mol H2/mol RS and published. I have developed a two stage biogas (biohydrogen and biomethane) process from waste fractions which are considerably generated from bioethanol process. I have successfully treated extractive via anaerobic digestion for biomethane to bring COD value below 250 to recycle processed water for reutilization. This was helped to reduce economic constrain of bioethanol process and would facilitate onsite utilization of biogas in boilers, heating and lighting the facility. Both bench scale and pilot scale studies were undertaken with techno-economic analysis to economies overall bioethanol technology.

 (7) Investigation of unique organic acid supplementation ratio in production media for enhanced biohydrogen production.  A novel finding of this research was enhancement of biohydrogen production by exploitation of stress conditions. Stress was maintained via three organic acids supplementation in appropriate ratio which facilitated improvement in product yield and negatively affected growth of bacteria.  It was a novel idea and nowhere reported in previous studies. Moreover, none of the biohydrogen study has been reported this level of yield (4.5 mol/mol red sugar) improvement so far. We obtained a USA process patent (US 2017/0226536A1 IOCL/IP/2014-15/27,) from this study. This would lead to reduce economic constrain on large scale biohydrogen production process. Whole Genome of best BioH2 producer in-house culture Clostridium Sp IODB-O3 has been sequenced and related genes annotated to understand its mechanism and potential for biofuel application. This WGS project has been deposited at DDBJ/EMBL/GenBank under the accession no. LIGD00000000.  

(8) Development of maximum sulfur capture strategies on biochar and application of sulfur-laden biochar for sulfur nutrition in plants

I worked as Research Scientist at Department of Biosciences and Bioengineering, University of Hawaii at Manoa, United States. The area of my research here was Environmental Bioengineering, broadly focused on conversion of waste into value-added products and environmental remediation. The specific project was on the conversion of anaerobically digested waste biomass into biochar, physicochemical characterization of biochar and H2S/SO2 adsorption on designer biochar surface and subsequent application of the resulting S-laden biochar for sulfur nutrition to the plants (Zea mays). Green house pot experiments were successfully completed with the proof that S-biochar helped in S nutrition to corn plants in S-deficient soil. Obtained one publication on the topic studied.

(9) Development of strategies for effective management of food waste in conventional sewage sludge reactors for methane production

I have studied various ratios of food waste blending into primary and secondary sewage sludge in a conventional AD facility to cope up challenge of highly organic nature of food waste for its effective treatment. We found 1/9 was effective blending ratio to reduce the problem raised via solitary AD process of food waste by acid struck and stabilize the process. It helped to address a cheaper and existing technology for its effective management in the present scenario. Obtained one publication on the topic studied.

 (10) Currently developing the effective mixotrophic microalgae cultivation methods to obtained maximum biomass/lipid fractions. Split mixotrophic cultivation strategy (SMCS) has been demonstrated for several offered advantages and synergistic-growth effects. We successfully filed a patent over this process for designing the bioreactor and cultivation methods which enable us to cope up mixotrophic associated challenges and regain the loss of biomass/product due to organic supplementation associated effects. The process showed that SMCS as better cultivation strategy than the general mixotrophy by offering increased biomass and lipid yields. Challenges associated with organic carbon can be solved by SMCS viz. chlorophyll loss, organic carbon uptake inhibition. SMCS could be a breakthrough to integrate bacterial process with algae for better bioprocess economy and energy recovery

I have an average H factor 47 and citations over 9550 (Google Scholar). I am the recipient of the Young Scientist Award from an International Forum of Industrial Bioprocesses (IBA) at Lille, France (2013), the Bioscience Energy Overseas fellowship (2013) by DBT, Ministry of Science and Technology India and the Pandey Research Excellence Award (2022). I have over 140 publications/communications, which include 04 patents, 110 original and review articles, 37 book chapters, and 2 conference proceedings etc. I was the Conveyer of the X-IBA International Conference inviting over 100 delegates from 34 countries. I have delivered several invited lectures and conference communications as oral and posters. I have chaired several sessions in international conferences and worked as a potential reviewer in several peer reviews journals. I have served as Guest Editor for special issues of the journals: Bioresource Technology (2019, 2022, 2021, 2022) and Applied Sciences (2019); Science of the Total Environment (2021). I have worked as a key coordinator for scientific sessions at several overseas international conferences.  Moreover, Editorial board member of Bioengineered, Heliyon, Applied Sciences, and Journal of Environmental Science and Engineering etc.