Statistical Optimization of Fermentation Process Parameters by Taguchi Orthogonal Array Design for Improved Bioethanol Production

• Published in: Journal of Fuels 2014-01, Vol.2014, p.1-11
• Main Authors: Das, Saprativ P., Das, Debasish, Goyal, Arun
• Format: Article
• Language: English
• ISSN: 2356-7392; 2314-601X
• DOI: 10.1155/2014/419674

The statistical optimization of different fermentation process parameters in SSF of mixed MAA and organosolv pretreated 1% (w v−1) wild grass, namely, recombinant Clostridium thermocellum hydrolytic enzymes’ volume (GH5 cellulase, GH43 hemicellulase), fermentative microbes’ inoculum volume (Saccharomyces cerevisiae, Candida shehatae), pH, and temperature, was accomplished by Taguchi orthogonal array design. The optimized parameters in 100 mL of fermentation medium were (%, v v−1) as follows: 1.0, recombinant GH5 cellulase (5.7 mg−1, 0.45 mg mL−1); 2.0, recombinant GH43 hemicellulase (3.7 U mg−1, 0.32 mg mL−1); 1.5, S. cerevisiae (3.9 × 108 cells mL−1); 0.25, C. shehatae (2.7 × 107 cells mL−1); pH, 4.3; and temperature, 35∘C. pH with p-value 0.001 was found to be the most significant factor affecting SSF. The ethanol titre obtained in Taguchi optimized shake flask SSF was 2.0 g L−1 implying a 1.3-fold increase as compared to ethanol titre of 1.5 g L−1 in unoptimized shake flask SSF. A 1.5-fold gain in ethanol titre (3.1 g L−1) was obtained with the same substrate concentration in lab scale bioreactor on scaling up the shake flask SSF with Taguchi optimized process parameters.