University of Toledo : Chemical and Environmental Engineering

1975 B.S. in Chemical Engineering, Andhra University, India
1977 M.S.Ch.E., Indian Institute of Technology, Kanpur
1983 Ph.D. in Chemical Engineering, State University of New York at Buffalo

Our current research activities are mainly in three areas: (1) using ionic liquids (ILs) as “green solvents”; (2) biocatalysis; and (3) colloids and surface phenomena. In the first area, we are interested in the use of ILs (i) for pretreatment of biomass to achieve enhanced enzymatic saccharification for fuel and chemical production, and (ii) as extracting solvents for bioproducts. In the area of biocatalysis, we are using immobilized enzyme catalysis and fermentations involving native and genetically engineered microorganisms (GMOs). In the third area, we are applying the principles of colloidal and surface phenomena in separation processes. Our applications include protein crystal nucleation kinetics and membrane separation processes (facilitated transport & active transport).

K. Rao, S. Chelikani, P. Relue, and S. Varanasi, “A Novel Technique for Optimizing the Simultaneous-Isomerization-and-Fermentation (SIF) Approach of Converting Xylose to Ethanol,” Applied Biochemistry and Biotechnology, 146(1-3):101-117 (2008).

A. P. Dadi, C. A. Schall and S. Varanasi, “Mitigation of cellulose recalcitrance to enzymatic hydrolysis by Ionic Liquid Pretreatment,” Applied Biochemistry and Biotechnology, 136-140:407-421 (2007).

K. Rao, V. Chaudari, D.-S. Kim, and S. Varanasi, “Enhanced Ethanol Fermentation of Brewery Waste Water Using the Genetically Modified Strain, E. coli KO11,” Applied Microbiology and Biotechnology, 74:50-60 (2007).

A. P. Dadi, S. Varanasi and C. A. Schall, “Enhancement of cellulose saccharification Kinetics using an ionic liquid pretreatment step,” Biotechnology and Bioengineering, 95:904-910 (2006).

G. Chen, R. Fournier and S. Varanasi, “Mathematical Model for the Generation and Control of pH Gradient in an Immobilized Enzyme System Involving Acid Generation,” Biotechnology and Bioengineering, 57:394-408 (1998).

G. Chen, R. Fournier and S. Varanasi, “Experimental Demonstration of pH Control for a Sequential Two-Step Enzymatic Reaction,” Enzyme & Microbial Technology, 21:491-495 (1997).

G. Chen, R.L. Fournier, P.A. Mahama and S. Varanasi, “Helicobacter pylori Survival in Gastric Mucosa by Generation of a pH Gradient,” Biophysical Journal, 73:1081-1088 (1997).

S. Varanasi, G. Chen, J. Byers and R.L. Fournier, "Optimal pH Control in Sequential Biochemical Reaction Systems via Generating a pH Gradient Across an Immobilized Enzyme Film," in book, Biofunctional Membranes, D. A. Butterfield (ed.), Plenum Press, p.173-91 (1996).

J.P.Byers, G. Chen, R. Fournier and S. Varanasi, “Demonstration of pH Control in a Commercial Immobilized Glucose Isomerase,” Biotechnology and Bioengineering, 52:718-722 (1996).

S. Asthana, R. Lemert and S. Varanasi, "2 Vinyloxy Ethyl Phthalimide Polymerization Initiated by 1-(Isobutoxy) Ethyl Acetate in the Presence of Ethyl Aluminum Dichloride and either Ethyl Acetate or Ethyl Benzoate,” Journal of Polymer Science: Part A - Polymer Chemistry, 34:1993-2001 (1996).

Y. Chu, M. McGlade, P.P. Varanasi and S. Varanasi, “pH Induced Swelling Kinetics of Polyelectrolyte Hydrogels,” Journal of Applied Polymer Science, 58:2161-76 (1995).

J.P. Byers, R.L. Fournier, and S. Varanasi, “A Feasibility Analysis of a Novel Approach for the Conversion of Xylose to Ethanol,” Chemical Engineering Communications, 112:165-187 (1992).

S. O. Ogundiran, and S. Varanasi, “Modeling of Enzyme–Potentiometric Sensors involving Acid– or Base–Forming Reactions,” Biotechnology and Bioengineering, 37:160–176 (1991).

S. Misra and S. Varanasi, "Effect of the finite extensibility of polymer chains and of the finite size of added electrolyte ions on polyelectrolyte brushes," Journal of Chemical Physics, 95(3): 2183-2192 (1991).

R.L. Stevens, and S. Varanasi, “Design of Enzyme-pH Electrodes,” AIChE Journal, 33:558-572 (1987).

“A Novel technique that enables efficient fermentation of xylose and hexose sugars from biomass hydrolysates using native non-GMO yeasts,” S. Varanasi, K. Rao and P. Relue, US utility patent application filed, January 2009.

“Pretreatment of Biomass”, S. Varanasi, C. Schall, Anatharam, P. Dadi, J. Anderson, K.Rao, P. Paripati, and G. Kumar, US utility patent application filed, Application Filing # 60/894708.

“Saccharifying Cellulose”, S. Varanasi, C. Schall and Anatharam P. Dadi, US utility patent application; Application Filing # 11/710,357.

"Bilayer Pellet Containing Immobilized xylose Isomerase and Urease for the Simultaneous Isomerization and Fermentation of Xylose to Ethanol, J.P. Byers, R.L. Fournier, and S. Varanasi, US Patent # 5,254,468.

“Method of Producing Products with a Bilayer Pellet Containing A Coimmobilized Enzyme System That Maintains a pH Difference,” J.P. Byers, R.L. Fournier, and S. Varanasi, US Patent # 5,397,700.

Department of Energy University Research Program

Department of Energy SBIR Program

USDA SBIR Program

Consortium for Plant Biotechnology Research