2-18: Obtaining of L-lactic acid using Lactobacillus ssp.: optimization of the culture medium composition for sugar cane molasses fermentation

The lactic acid, in addition to its usual applications, also has the latest application in Tissue Engineering through the synthesis of poly L-lactic acid (PLLA) for subsequent synthesis of scaffolds, pins and screws. The use of biotechnology in the production of sustainable products from renewable resources is being increasingly practiced through green chemistry and biotechnology. The use of alternative substrates in fermentation processes in order to take advantage of agricultural raw materials of low cost or byproducts from various industries (molasses, corn syrup, whey, etc) decreases the cost of culture medium used and hence the final product. Bearing this in mind, the objectives of this work consists on optimizing the production of L-lactic acid from fermentation processes, aiming high product yield, selectivity, productivity and reduced cost by the use of sugar cane molasses as alternative substrates. It is intended to gain a better understanding of the interaction between the microorganisms and its environment and regulation of microbial metabolic pathway. Two Lactobacillus ssp. producing L-lactic acid isomer were selected from literature. The optimizing of the culture medium composition was performed from experimental design followed by bench testing taking into account temperature and concentration of sucrose and yeast extract. From these data, the bioreactor fermentations were performed with the best conditions obtained for each strain. The next and future step will be a separation and purification process to obtain the L-lactic acid pure isomer.