Dr. Karan Kumar

Doctoral Thesis Research

Short Abstract

Thesis Title: Investigations in Enhanced Production of Bio-alcohols and their Derivatives using Experimental and in-Silico Approach

This thesis presents a comprehensive scientific investigation focusing on the challenges and advancements in bioalcohol (mainly biobutanol) synthesis through clostridia, emphasizing enhancing production efficiency from sustainable resources. Employing a multidisciplinary approach, the research encompasses comparative genomic analysis, in-depth exploration of cell central metabolism during Acetone-Butanol-Ethanol (ABE) fermentation, experimental examination of butanol production from lignocellulosic hydrolysates using clostridial co-culture systems, development of genome-scale metabolic models (GSMs), and innovative investigations into the production of value-added bioalcohol using sono-enzymatic processes.

A key finding of the comparative genomic analysis is the successful identification of potential butanol-producing Clostridium species with an accuracy of 78%. This result provides insights into the genetic basis of bioalcohol production, providing a solid foundation for formulating potential engineering strategies to optimize biofuel synthesis.

The thesis has also unveiled physiological disparities between C. acetobutylicum and C. pasteurianum during ABE fermentation. Notably, C. acetobutylicum demonstrated superior performance with 25% higher growth rates and an impressive 18% increase in butanol production from various carbon sources. This understanding of coregulatory mechanisms and stress responses provided important inputs for strain optimization for enhanced bioalcohol production from sustainable sources.

The investigation into the inhibition mechanisms of key aldehyde/alcohol dehydrogenases (AADs) in solventogenic species led to the identification of ρ-coumaric acid (ρ-CA) as the most potent inhibitor. Its binding affinity to seven modeled enzymes highlights ρ-CA's significance as a potential target for enhanced biobutanol production, offering avenues for increased yields and cost-effectiveness.

Statistical optimization of clostridial co-culture for bio-butanol production from mixed substrates resulted in exceptional yields of butanol (12.1 ± 0.45 g/L), biomass (4.15 ± 0.03 OD600), and ABE solvents (23.1 ± 0.55 g/L). The comprehensive Genome-scale models have given important insights into clostridial ABE fermentation, the metabolic pathways, and potential targets for enhanced bioalcohol production.

The exploration of sonication-induced enhancement in lipase-catalyzed reactions for biodiesel synthesis, increased enzyme activity, and faster reaction kinetics were observed. Structural modifications in lipases resulted in a higher yield of n-butyl levulinate (n-BL), opening promising avenues for efficient biodiesel production.

In conclusion, this thesis significantly contributes to the scientific understanding of clostridial bioalcohol synthesis, offering vital knowledge for optimal strain selection, potential engineering strategies, and advancements in sustainable bioenergy production. Essentially, this dissertation has contributed to 3 among the 17 Sustainable Development Goals (SDGs) established by the United Nations in 2015, with the aim of achieving a more sustainable and inclusive future for all: (1) Goal 7 (affordable and clean energy), (2) Goal 11 (sustainable cities and communities), and (3) Goal 13 (climate action).

Aim & Scope of Doctoral Thesis

This work aims to develop and investigate an efficient and sustainable approach to enhance the production of bio-alcohols and their derivative for bioenergy applications using various experimental and in-silico techniques. The thesis entitled “Investigations in Enhanced Production of Bio-alcohols and their Derivatives using Experimental and In-Silico Approach” has been divided into five main objectives, which are given below. Click here for the detailed publication profile of my PhD thesis work.

Objective 1: Comparative genomic analysis of potential butanol-producing Clostridium sp. to identify best solventogenic and cellulolytic Clostridia

Objective 2: Investigation of cell central metabolism for a better understanding of the biochemistry and physiology of ABE fermentation

Objective 3: Study of the challenges and scope of butanol production from lignocellulosic hydrolysates using Clostridial co-culture system

Objective 4: Development and applications of GSMs for understanding Clostridium ABE fermentation and devising metabolic engineering strategies for higher yields of biobutanol

Objective 5: Investigations in enhanced production of derivatives of bioalcohols using sono-enzymatic processes: experimental and computational approach

Doctoral Team

Professor V. S. Moholkar

Dr. Vijayanand Suryakant Moholkar (b. 1972) is a Professor (HAG) of Chemical Engineering and Adjunct Faculty at School of Energy Science and Engineering (erstwhile Centre for Energy) at Indian Institute of Technology (I.I.T.) Guwahati. He received B. Chem. Engg. (1993) and M. Chem. Engg. (1996) degrees in chemical engineering from Institute of Chemical Technology (formerly University Department of Chemical Technology, UDCT) Mumbai, followed by Ph.D. from University of Twente (Netherlands) in 2002. He has been Head of the Chemical Engineering Department between 2012-2015, and Head of Centre for Energy between 2017-2020. His main research interests are sonochemistry, cavitation assisted physical, chemical and biological processing, and thermo- and biochemical routes to biofuels. As of June 2021, he has published more than 195 papers in renowned international journals that have received more than 10500 citations (with h-index of 59). He is co-inventor of 3 US patents (issued to CTI Nanotech, CA, USA) on application of hydrodynamic cavitation reactors for biomass pretreatment and bioalcohol synthesis. As of October 2022, he has graduated 25 Ph.D. and 32 M.Tech. students. He has been elected as Fellow of Royal Society of Chemistry (FRSC) in July 2016. He has also been elected as Fellow of Institution of Chemical Engineers, UK. He is a Chartered Engineer (CEng) registered with Engineering Council of UK. He was admitted as Senior Member of American Institute of Chemical Engineers (MAIChE (Sr.)) in August 2016. His name has consistently featured in the list of world's top 2% scientists published by Stanford University, USA for the years 2020, 2021 and 2022.

Karan Kumar is a research scholar at Indian Institute of Technology (IIT), Guwahati. He received his bachelor's degree (2018) in Biotechnology from National Institute of Technology (NIT), Calicut. He is conferred with the prestigious Prime Minister's Research Fellowship to pursue doctoral studies in the Interdisciplinary areas of Science and Engineering (IDSE) and joined IIT Guwahati under the joint supervision of Professor V. S. Moholkar and Dr. L. Barbora. He is also the recipient of the prestigious AcSIR- Dr A.P.J Abdul Kalam Summer Research Fellowship (2017). Broadly, Karan does research in the core areas of Biotechnology and Environmental Engineering. He is currently working on a novel technique for investigating and enhancing the production of alcoholic biofuels in solventogenic bacteria. His research interest lies in applying state-of-the-art techniques from mathematical biology, bioinformatics, and computational biology to understand biological systems and their behavior in complex environments. His current research works include molecular dynamic simulation, production of alcoholic biofuel, and mathematical modeling of enzymatic reactions. He has published and co-authored in highly repute journals such as Energy Conversion and Management (I.F 9.7, Q1), Algal Research (IF 4.5, Q1) and Process Biochemistry (IF 3.8, Q1).

Dr. Lepakshi Barbora

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