Improving the fermentation performance of saccharomyces cerevisiae by laccase during ethanol production from steam-exploded wheat straw at high-substrate loadings

• Published in: Biotechnology progress 2013-01, Vol.29 (1), p.74-82
• Main Authors: Alvira, Pablo, Moreno, Antonio D., Ibarra, David, Sáez, Felicia, Ballesteros, Mercedes
• Format: Article
• Language: English
• Subjects: Ethanol - analysis; Ethanol - metabolism; ethanol production; Fermentation - drug effects; Furans - pharmacology; high-substrate loadings; Hydrolysis; laccase; Laccase - antagonists & inhibitors; Laccase - metabolism; Plant Components, Aerial - chemistry; Plant Components, Aerial - metabolism; Pycnoporus - enzymology; Saccharomyces cerevisiae; Saccharomyces cerevisiae - drug effects; Saccharomyces cerevisiae - growth & development; Saccharomyces cerevisiae - metabolism; Steam; steam-exploded wheat straw; Triticum - chemistry; Triticum - metabolism
• ISSN: 8756-7938; 1520-6033
• DOI: 10.1002/btpr.1666

Operating the saccharification and fermentation processes at high‐substrate loadings is a key factor for making ethanol production from lignocellulosic biomass economically viable. However, increasing the substrate loading presents some disadvantages, including a higher concentration of inhibitors (furan derivatives, weak acids, and phenolic compounds) in the media, which negatively affect the fermentation performance. One strategy to eliminate soluble inhibitors is filtering and washing the pretreated material. In this study, it was observed that even if the material was previously washed, inhibitory compounds were released during the enzymatic hydrolysis step. Laccase enzymatic treatment was evaluated as a method to reduce these inhibitory effects. The laccase efficiency was analyzed in a presaccharification and simultaneous saccharification and fermentation process at high‐substrate loadings. Water‐insoluble solids fraction from steam‐exploded wheat straw was used as substrate and Saccharomyces cerevisiae as fermenting microorganism. Laccase supplementation reduced strongly the phenolic content in the media, without affecting weak acids and furan derivatives. This strategy resulted in an improved yeast performance during simultaneous saccharification and fermentation process, increasing significantly ethanol productivity. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013