Lactic acid production from Cellobiose and xylose by engineered Saccharomyces cerevisiae

Authors: TURNER, TIMOTHY - University Of Illinois; ZHANG, GUO-CHANG - University Of Illinois; OH, EUN - University Of Illinois; SUBRAMANIAM, VIJAY - University Of Illinois; ADIPUTRA, ANDREW - University Of Illinois; SUBRAMANIAM, VIMAL - University Of Illinois; Skory, Christopher - Chris; JANG, JI YEON - Korea Institute Of Industrial Technology (KITECH); YU, BYUNG YU - Korea Institute Of Industrial Technology (KITECH); PARK, IN - Korea Institute Of Industrial Technology (KITECH); JIN, YONG-SU - Korea Institute Of Industrial Technology (KITECH)

Submitted to: Biotechnology and Bioengineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/3/2015
Publication Date: 11/20/2015
Citation: Turner, T.L., Zhang, G.C., Oh, E.J., Subramaniam, V., Adiputra, A., Subramaniam, V., Skory, C.D., Jang, J.Y., Yu, B.J., Park, I., Jin, Y.S. 2015. Lactic acid production from cellobiose and xylose by engineered Saccharomyces cerevisiae. Biotechnology and Bioengineering. 113(5):1075-1083. doi: 10.1002/bit.25875.

Interpretive Summary: Production of lactic acid from renewable sugars has received growing attention as lactic acid is used for making renewable and bio-based plastics. This organic acid is typically made by microorganisms that are able to ferment sugars obtained from agricultural or energy crops into this important product. Most prior studies have focused on production of lactic acid from glucose despite an abundance of the sugar xylose and cellobiose in hydrolyzed plant biomass. Microbial strains capable of fermenting xylose and cellobiose into lactic acid are needed for sustainable and economic lactic acid production. In this study, a lactic acid-producing pathway was introduced into an engineered Saccharomyces cerevisiae capable of fermenting xylose and cellobiose. The resulting strain produced lactic acid from these sugars in high yields. This work is expected to be a significant contribution towards the development of improved technologies for producing lactic acid.

Technical Abstract: Efficient and rapid production of value-added chemicals from lignocellulosic biomass is an important step towards a sustainable society. Lactic acid, used for synthesizing the bioplastic polylactide, has been produced by microbial fermentation using primarily glucose. Lignocellulosic hydrolysates contain high concentrations of cellobiose and xylose. Here, we constructed a recombinant Saccharomyces cerevisiae strain capable of fermenting cellobiose and xylose into lactic acid. Specifically, genes coding for cellobiose transporter, ß-glucosidase, xylose reductase, xylitol dehydrogenase, xylulokinase, and lactate dehydrogenase were integrated into the S. cerevisiae chromosomes. The resulting strain produced lactic acid from cellobiose or xylose with high yields. When fermenting a cellulosic sugar mixture containing 10 g/L glucose, 40 g/L xylose, and 80 g/L cellobiose, the engineered strain produced 83 g/L of lactic acid with a yield of 0.66 g lactic acid/g sugar. This study demonstrates the feasibility of economic and sustainable production of lactic acid from lignocellulosic hydrolysates.