Lactic Acid Fermentation of Sporolactobacillus in Glucose and Biomass-Derived Sugars

Lactic acid has a wide array of applications in the food-processing and pharmaceuticals, and its derivative, polylactic acid (PLA) can be developed into an environmentally-friendly biodegradable thermoplastic. Industrial lactic acid production has focused on utilizing bacterial fermentation rather than synthesis due to high manufacturing cost, less sustainability, and the inability to form the D-lactic acid stereoisomer.This D-lactic acid stereoisomer is combined with L-lactic acid to form stereocomplex polylactic acid, which can lead to a more thermally resistive plastic. The D-lactic acid stereoisomer is desired to form a stereocomplex polylactic acid, which could lead to a more thermally resistive plastic. This study attempted to test the D-lactic acid fermentation of a Sporolactobacillus strain in glucose media and HTM, a sugar cane biomass feedstock, before scale-up. D-lactic acid titer was measured by using YSI and HPLC, and growth of the strain was monitored by measuring OD and pH. Bacteria in HTM was found had a 68% higher productivity while bacteria in a glucose environment had a 22% higher yield. These results will help determine the future scalability of this strain.