University of California, Riverside

Center for Environmental Research & Technology



Rajeev Kumar, PhD


Rajeev

Background :

Dr. Rajeev Kumar is an Associate Research Engineer (Research Faculty) at the Bourns College of Engineering Center for Environmental Research and Technology (CE-CERT) of the University of California, Riverside. He comes to the center from Zymetis, Inc. of College Park, Maryland where he was Director of Enzyme Product Development. Dr. Kumar earned his Ph.D. in Biochemical and Chemical Engineering from Thayer School of Engineering at Dartmouth College, Hanover, NH, USA. He got his Masters and Bachelor’s Degrees both in Chemical Engineering from the Indian Institute of Technology, Kanpur, India and SLIET Longowal (Punjab Technical University), Sangrur, Punjab, India, respectively.

Research :

Dr. Kumar has been working on understanding the fundamentals of lignocellulosic biomass recalcitrance to biological breakdown, developing novel routes to biomass conversion, and enhancing product yields from existing routes for the last ten years. He is well published with over 45 international journal articles and 6 book chapters and his area of expertise are: lignocellulosic biomass fractionation, cellulosic biomass saccharification, enzyme-substrate interactions, substrate physiochemical characterizations, and kinetics.

Peer Reviewed Publications:    

  • Bhagia S., Kumar R., Wyman C.E. 2017. “Effects of Dilute Acid and Flowthrough Pretreatments and BSA Supplementation on Enzymatic Deconstruction of Poplar by Cellulase and Xylanase,” Carbohydrate Polymers, 157, 1940-1948. 
  • Bhagia S., Li H., Gao X., Kumar R., Wyman C.E. 2016. “Flowthrough Pretreatment with Very Dilute Acid Provides Insights into High Lignin Contribution to Biomass Recalcitrance,” Biotechnology for Biofuels, 9, 245.
  • Bhagia S., Nunez A., Wyman C.E., Kumar R. 2016. “Robustness of Two-Step Acid Hydrolysis Procedure for Composition Analysis of Poplar,” Bioresource Technology, 216, 1077-1082.
  • Horváth I.S., Tabatabaei M., Karimi K., Kumar R. 2016. “Recent Updates on Biogas Production - a Review,” Biofuel Research Journal, 2(3), 394-402.
  • Bhagia S., Muchero W., Kumar R., Tuskan G.A., Wyman C.E. 2016. “Natural Genetic Variability Reduces Recalcitrance in Poplar,” Biotechnology for Biofuels, 9:106.
  • da Costa Sousa L., Jin M., Chundawat S., Bokade V., Tang X., Ali A., Lu F., Avici U., Humpula J., Uppugundla N., Gunawan C., Pattathil S., Cheh A., Kothari N., Kumar R., Ralph J., Hahn M., Wyman C.E., Singh S., Simmons B., Dale B., and Balan V. 2016. “Next-Generation Ammonia Pretreatment Enhances Cellulosic Biofuel Production,” Energy and Environmental Science, 9, 1215-1223. (Paper highlighted by Green Car Congress and several other news media). 
  • Kumar R, Tabatabaei M., Karimi K., Horváth I.S. 2016. "Recent Updates on Lignocellulosic Biomass Derived Ethanol-A Review,” Biofuel Research Journal, 3(1), 347-356.
  • Karimi K., Tabatabaei M., Horváth I.S., Kumar R. 2015. “Recent Trends in Acetone, Butanol, and Ethanol (ABE) Production,” Biofuel Research Journal, 2(4), 301-308.
  • DeMartini J. D., Foston M., Meng X., Jung S., Kumar R., Ragauskas A.J., Wyman C. E. 2015. “How Chip Size Impacts Steam Pretreatment Effectiveness for Biological Conversion of Poplar Wood into Fermentable Sugars,” Biotechnology for Biofuels, 8: 209.
  • Nguyen Y.T., Cai C.M., Osman, O., Kumar R., Wyman C.E. 2016. “CELF Pretreatment of Corn Stover Boosts Ethanol Titers and Yields from High Solids SSF with Low Enzyme Loadings,” Green Chemistry, 18, 1581-1589.
  • Tabatabaei M., Karimi K., Horváth I.S., Kumar R. 2015. “Recent Trends in Biodiesel Production,” Biofuel Research Journal, 2(3), 258-267.
  • Tabatabaei M, Karimi K, Kumar R, Horváth IS. 2015. "Renewable Energy and Alternative Fuel Technologies," BioMed Research International, 2.
  • Nguyen YT, Cai CM, Kumar R, and Wyman CE. 2014. “THF Co-Solvent Pretreatment Achieves Unprecedented Total Sugar Recovery and Ethanol Yields from Lignocellulosic Biomass at Low Enzyme Loadings,” ChemSusChem, 8, 1716-1725. (Featured in Biomass Magazine, ScienceDaily®, and several other news media).
  • Singh S, Cheng G, Sathitsuksanoh N, Wu D, Varanasi P, George A, Balan V, Gao X, Kumar R, Dale BE, and Wyman CE, and Simmons BA. 2014. “Comparison of Different Biomass Pretreatment Techniques and their Impact on Chemistry and Structure,” Frontiers in Energy Research, 2.
  • Zhang T, Kumar R, Tsai YD, Elander R, and Wyman CE. 2015. "Xylose Yields and Relationship to Combined Severity for Dilute Acid Post-Hydrolysis of Xylooligomers from Hydrothermal Pretreatment of Corn Stover," Green Chemistry, 17 (1), 394-403.
  • Sun Q, Foston M, Meng X, Sawada D, Pingali S, O'Neill H, Li H, Wyman C, Langan P, Ragauskas A, and Kumar R. 2014. "Effect of Lignin Content on Changes Occurring in Poplar Cellulose Ultrastructure during Dilute Acid Pretreatment," Biotechnology for Biofuels, 7(1), 150.
  • Cai CM, Nagane N, Kumar R, and Wyman CE. 2014. "Coupling Metal Halides with a Green Co-Solvent to Produce Furfural and 5-HMF at High Yields Directly from Lignocellulosic Biomass as an Integrated Biofuels Strategy," Green Chemistry, 16, 3819-3829.(Featured in DailyNews, ScienceDaily®, and several other news media).
  • Kumar R and Wyman CE. 2014. "Strong Cellulase Inhibition by Mannan Polysachharides in Cellulose Conversion to Sugars," Biotechnology and Bioengineering, 111 (7), 1341-1353. (This article showed for the first time the strong inhibitory effects of mannan polysaccharides and their oligomers on cellulase in cellulose conversion to sugars. Featured in the "Spotlight" section of the issue). 
  • Uppugundla N, Sousa LDC, Chundawat SPS, Yu X, Simmon B, Singh S, Gao X, Kumar R, Wyman CE, Dale BE, and Balan V. 2014. “A Comparative Study of Ethanol Production using Dilute Acid, Ionic Liquid, and AFEX Pretreated Corn Stover,” Biotechnology for Biofuels,  7:72.(One of the most viewed articles).
  • Gao X, Kumar R, Singh S, Simmon B, Balan V, Dale B, and Wyman CE. 2014. “Comparison of Enzymatic Reactivity of Corn Stover Solids Prepared by Dilute Acid, AFEX, and Ionic Liquid Pretreatments,” Biotechnology for Biofuels, 7:71.
  • Gao X, Kumar R, and Wyman CE. 2014 .“Fast Hemicellulose Quantification via a Simple One-step Acid Hydrolysis,” Biotechnology and Bioengineering, 111 (6), 1088-1096.
  • Li H, Pattathil S, Foston MB, Ding S, Kumar R, Gao X, Mittal A, Yarbrough JM, Himmel ME, Ragauskas AJ, Hahn MG,  and Wyman CE. 2014. “Agave Proves to be a Low Recalcitrant Lignocellulosic Feedstock for Biofuels Production on Semi-arid Lands,” Biotechnology for Biofuels, 7:50.
  • Bond JQ, Upadhye AA, Olcay H, Tompsett G, Jae J, Xing R, Alonso DM, Wang D, Zhang T, Kumar R, Foster A, Sen SM, Maravelias CT, Malina R, Barrett SRH, Lobo R, Wyman CE, Dumesic JA, and Huber GW. 2014. “Production of Renewable Jet Fuel Range Alkanes and Commodity Chemicals from Integrated Catalytic Processing of Biomass,” Energy and Environmental Science, 7 (4), 1500-1523. (Featured in ScienceDaily® and several other news media).
  • Zhang M, Chen G, Kumar R, and Xu B. 2013. "Mapping Out the Structural Changes of Natural and Pretreated Plant Cell Wall Surfaces by Atomic Force Microscopy Single Molecular Recognition Imaging," Biotechnology for Biofuels, 6 (1), 147.
  • Li H, Pu Y, Kumar R, Ragauskas AJ, and Wyman CE. 2013. "Investigation of Lignin Deposition on Cellulose during Hydrothermal Pretreatment, its Effect on Cellulose Hydrolysis, and Underlying Mechanisms," Biotechnology and Bioengineering, 111 (3), 485-492.
  • Cai CM, Zhang T, Kumar R, and Wyman CE. 2013. "THF Co-solvent Enhances Hydrocarbon Fuel Precursor Yields from Lignocellulosic Biomass," Green Chemistry, 15, 3140-3145. (One of the HOT papers in Green Chemistry)
  • Cai CM, Zhang T, Kumar R, and Wyman CE. 2013. “Integrated Furfural Production As A Renewable Fuel And Chemical Platform From Lignocellulosic Biomass,” Journal of Chemical Technology and Biotechnology, 89 (1), 2-10.
  • Li H, Gao X, DeMartini JD, Kumar R, and Wyman CE. 2013. “Application of High Throughput Pretreatment and Co-Hydrolysis System to Thermochemical Pretreatment. Part 2: Dilute Alkali," Biotechnology and Bioengineering, 110 (11), 2894-2901.
  • Zhang T, Kumar R, and Wyman CE. 2013. " Enhanced Yields of Furfural and Other Products by Simultaneous Solvent Extraction during Thermochemical Treatment of Cellulosic Biomass," RSC Advances, 3 : 9809-9819.
  • Li H, Qing Q, Kumar R, and Wyman CE. 2013. “Chromatographic Determination Of 1, 4-Β-Xylooligosaccharides Of Different Chain Lengths To Follow Xylan Deconstruction In Biomass Conversion," Journal of Industrial Microbiology and Biotechnology, 40 (6) : 551-559.
  • Kumar R, Hu F, Hubbell CA, Ragauskas AJ, and Wyman CE. 2013.“Comparison of Laboratory Delignification Methods, Their Selectivity, and Impacts on Physiochemical Characteristics of Cellulosic Biomass,” Bioresource Technology, 130: 372-381.
  • Gao X, Kumar R, DeMartini JD, Li H, and Wyman CE. 2013 “Application of High Throughput Pretreatment and Co-Hydrolysis System to Thermochemical Pretreatment. Part1: Dilute Acid “, Biotechnology and Bioengineering, 110 (3): 754-762.
  • Kumar R, Hu F, Sannigrahi P, Jung S, Ragauskas AJ, and Wyman CE., 2013. “Carbohydrate Derived Pseudo-Lignin Can Retard Cellulose Biological Conversion,” Biotechnology and Bioengineering, 110 (3): 737-753.
  • Zhang T, Kumar R, Wyman CE. 2013. "Comparison of Glucose and Xylose Yields from Dilute Oxalic Acid Pretreatment Followed by Enzymatic Hydrolysis of Red Maple to Results with Dilute Sulfuric and Hydrochloric Acids and Just Hot Water," Carbohydrate Polymers, 92 (1) : 334-344.
  • Li, H, Foston, MB, Kumar R, Samuel R, Gao X, Hu F., Ragauskas AJ, and Wyman CE, 2012. “Chemical Composition and Characterization of Cellulose for Agave as a Fast Growing, Drought Tolerant Biofuels Feedstock”, RSC Advances, 2: 4951-4958.
  • Suvorov, M, Kumar, R, Zhang, H, and Hutcheson, S. 2011. “Novelties of the Cellulolytic System of a Marine Bacterium Applicable to Cellulosic Sugar Production,”Biofuels, 2 (1): 1-12,  PDF
  • Kumar R, Wyman CE. 2009. “Access of Cellulase to Cellulose and Lignin for Poplar Solids Produced by Leading Pretreatment Technologies,” Biotechnology Progress 25(3): 807-819. PDF(One of the 10 most downloaded articles in June 2009)
  • Kumar R, Wyman CE. 2009. “Does Change in Accessibility with Conversion Depend on Both the Substrate and Pretreatment Technology?” Bioresource Technology 100(18): 4193-4202. PDF
  • Kumar R, Wyman CE. 2009. “Effect of Xylanase Supplementation of Cellulase on Digestion of Corn Stover Solids Prepared by Leading Pretreatment Technologies,” Bioresource Technology, 100(18): 4203-4213.PDF( One of the Spotlights of the volume; One of the  25 most downloaded articles in 2009, from January to April)
  • Kumar R, Mago G, Balan V, Wyman CE. 2009. “Physical and Chemical Characterizations of Corn Stover and Poplar Solids Resulting from Leading Pretreatment Technologies Bioresource Technology 100(17): 3948-3962.  PDF(One of the top 25 hottest articles April to June 2009; One of the most cited articles published since 2009)
  • Kumar R, Wyman CE. 2009. “Cellulase Adsorption and Relationship to Features for Corn Stover Solids Produced by Leading Pretreatments,” Biotechnology and Bioengineering 103(2): 252-267.  PDF  
  • Kumar R, Wyman CE. 2009. “Effect of Additives on the Digestibility of Corn Stover Solids Following Pretreatment by Leading Technologies,” Biotechnology and Bioengineering, 102(6): 1544-1557. PDF
  • Kumar R, Wyman CE. 2009. “Effects of Cellulase and Xylanase Enzymes on the Deconstruction of Solids from Pretreatment of Poplar by Leading Technologies,” Biotechnology Progress 25(2): 302-314. (One of the most accessed articles in 2013; One of the 10 most downloaded articles in 2009, from May to August)
  • Kumar R, Wyman CE. 2009. “Effect of Enzyme Supplementation at Moderate Cellulase Loadings on Initial Glucose and Xylose Release from Corn Stover Solids Pretreated by Leading Technologies,” Biotechnology and Bioengineering 102(2): 457-467.  PDF  (This article showed for the first time the strong inhibitory effect of hemicellulose xylan oligomers on cellulase- a key enzyme in cellulose conversion to sugars. Featured in the "Spotlight" section of the issue. One of the 20 most downloaded articles in 2009, from January to April).
  • Kumar R, Wyman CE. 2008. “An Improved Method to Directly Estimate Cellulase Adsorption on Biomass Solids,” Enzyme and Microbial Technology, 42: 426–433.  PDF(This article showed for the first time that sugars can inhibit cellulase binding to substarte. One of the top 25 hottest articles April to June 2008)
  • Kumar R, Wyman CE. 2008. “The Impact of Dilute Sulfuric Acid on the Selectivity of Xylooligomer Depolymerization to Monomers,” Carbohydrate Research 343(2): 290-300.  PDF (Experimentally showed for the first time that hemicellulose xylan oligomers can directly degrade to degradations products).

Book Chapter/s :

  • Kumar R., Wyman CE. 2010. “Features Controlling Hydrolysis of Cellulose in Pretreated Biomass,” in Bioalcohol Production, Waldron K, Ed, Woodhead Publishing Ltd, Cambridge, UK, pp 73-121, May, invited.  PDF
  • Kumar R., Wyman CE. 2013. “Physical and Chemical Features Influencing Macro/Micro Accessibility of Pretreated Biomass that Impact Biological Processing” in Aqueous Pretreatment of Plant Biomass for Biological and Chemical Conversion to Fuels and Chemicals, Wyman CE, Ed, Wiley Blackwell, Oxford, UK, pp 281-310. (Proposed a novel concept of micro/macro-accessibility of lignocellulosic biomass).
  • Qing Q., Li H., Kumar R., and Wyman CE. 2013. “Xylooligosaccharides Production, Quantification, and Characterization in Context of Lignocellulosic Biomass Pretreatment” in Aqueous Pretreatment of Plant Biomass for Biological and Chemical Conversion to Fuels and Chemicals, Wyman CE, Ed, Wiley Blackwell, Oxford, UK, pp 391-415.
  • Wyman C.E., Dale B.E., Balan V., Elander R.T., Holtzapple M.T., Sierra-Ramirez R., Ladisch M.R., Mosier N., Lee Y.Y., Gupta R., Thomas S., Hames B., Warner R., and Kumar R. 2013. “Comparative Performance of Leading Pretreatment Technologies for Biological Conversion of Corn Stover, Poplar Wood, and Switchgrass to Sugars” in Aqueous Pretreatment of Plant Biomass for Biological and Chemical Conversion to Fuels and Chemicals, Wyman CE, Ed, Wiley Blackwell, Oxford, UK, pp 239-259. 
  • Karimi K., Shafiei M., and Kumar R. 2013. "Progress in Physical and Chemical Pretreatment of Lignocellulosic Biomass," in Biofuels and Biorefineries: Recent Developments, Gupta VK, Ed, Springer-Verlag GmbH, Germany, pp 53-96.
  • Shafiei M, Kumar R, Karimi K. 2015. “Pretreatment of Lignocellulosic Biomass,” in Lignocellulose-Based Bioproducts, Karimi K. (Ed), Springer International Publishing, Switzerland, pp. 85-154.

Books Edited

  • Kumar R, Singh S, Balan V., Editors. 2016. “Valorization of Lignocellulosic Biomass in a Biorefinery: From Logistics to Environmental and Performance Impact,” Biochemistry Research Trends Series, Nova Science Publisher, New York, 446  pages.  Available on Amazon.com                                                              
 Valorization of biomass

Invention Disclosures/Patents:

  • Cai CM, Zhang T, Kumar R, Wyman CE. 2014. “Co-Solvent to Produce Reactive Intermediates from Biomass,” PCT/US2014/035506, April.

  • Kumar R, Wyman CE. 2009. “Enzymatic Hydrolysis of Cellulosic Biomass through Enhanced Removal of Oligomers,” Patent application PCT/US2009/051737, July 24.

Professional Activities :

  • Section Editor: Biotechnology for Biofuels

  • Associate Editor: 3 Biotech
  • Associate Editor: Journal of Biomass to Biofuels

  • Editorial board member : Biotechnology for Biofuels- 2010-2015.

  • Reviewer for several international journals including AIChE, Applied Biochemistry and Biotechnology, Applied Microbiology and Biotechnology, Bioresource Technology, Biotechnology Progress, BioEnergy Research, Biofuels, BioResources, Biotechnology for Biofuels, Energy and Fuels, Fuel, Journal of Biobased Materials and Bioenergy, Natural Product Research, Proceedings of National Academy of Sciences (PNAS), PLosOne, Process Biochemistry (>120).

Honors and Distinctions:

  • 2014 Outstanding Reviewer Award by Biomass and Bioenergy Journal, Elsevier Ltd., Amsterdam, The Netherlands for outstanding contribution to the journal

  • Research article featured in the "Spotlight" section of Biotechnology and Bioengineering, July, 2014 Issue

  • One of the top 25 cited articles published since 2008 in Bioresource Technology

  • Research article featured in the "Spotlight" section of Biotechnology and Bioengineering, Feb, 2009 Issue

  • Two articles among the top 25 most cited articles published in 2009, 2010, and 2011 in Biotechnology and Bioengineering

  • One of the 10 most-cited articles published in 2009, 2010, and 2011 in Biotechnology Progress

  • 2011 Outstanding Reviewer Award by Bioresource Technology Journal, Elsevier Ltd., Oxford, for outstanding contribution to the journal

  • 2010 Outstanding Reviewer Award by Bioresource Technology Journal, Elsevier Ltd., Oxford, for outstanding contribution to the journal

  • Three articles placed among “Top 10 articles” published all time in biomass conversion domain- BioMedLib 2010

  • Kumar R. Wyman CE. 2009. “Access of Cellulase to Cellulose and Lignin for Poplar Solids Produced by Leading Pretreatment Technologies,” Biotechnology Progress 25(3): 807-819. PDF
  • Kumar R, Wyman CE. 2009. “Does Change in Accessibility with Conversion Depend on Both the Substrate and Pretreatment Technology?” Bioresource Technology 100(18): 4193-4202. PDF
  • Kumar R. Wyman CE. 2009. “Effect of Xylanase Supplementation of Cellulase on Digestion of Corn Stover Solids Prepared by Leading Pretreatment Technologies,” Bioresource Technology, 100(18): 4203-4213. PDF
  • Kumar R, Mago G, Balan V, Wyman CE. 2009. “Physical and Chemical Characterizations of Corn Stover and Poplar Solids Resulting from Leading Pretreatment Technologies Bioresource Technology 100(17): 3948-3962. PDF

·         Kumar R. Wyman CE. 2009. “Cellulase Adsorption and Relationship to Features for Corn Stover Solids Produced by Leading Pretreatments,” Biotechnology and Bioengineering 103(2): 252-267.  PDF  

·         Kumar R. Wyman CE. 2009. “Effect of Additives on the Digestibility of Corn Stover Solids Following Pretreatment by Leading Technologies,” Biotechnology and Bioengineering, 102(6): 1544-1557. PDF

  • Kumar R, Wyman CE. 2009. “Effects of Cellulase and Xylanase Enzymes on the Deconstruction of Solids from Pretreatment of Poplar by Leading Technologies,” Biotechnology Progress 25(2): 302-314. PDF 
  • KumarR, Wyman CE. 2009. “Effect of Enzyme Supplementation at Moderate Cellulase Loadings on Initial Glucose and Xylose Release from Corn Stover Solids Pretreated by Leading Technologies,” Biotechnology and Bioengineering 102(2): 457-467.  PDF 
  • Kumar R, Wyman CE. 2008. “An Improved Method to Directly Estimate Cellulase Adsorption on Biomass Solids,” Enzyme and Microbial Technology, 42: 426–433.  PDF
  • Kumar R, Wyman CE. 2008. “The Impact of Dilute Sulfuric Acid on the Selectivity of Xylooligomer Depolymerization to Monomers,” Carbohydrate Research 343(2): 290-300.  PDF

More Information 

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Riverside, CA 92521
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Center for Environmental Research & Technology
1084 Columbia Avenue
Riverside, CA 92507
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Fax: (951) 781-5790
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