Darly Silvana Parrado, Alejandro Villegas and Juan Carlos Serrato
Providencia Sugar Mill, Production Plant of Special Alcohols, Colombia; dsparrado@providenciaco.com
This study assessed the vaporization of co-products from the industrial transformation of sugarcane and ethanol as part of the culture medium evaluated to produce lactic acid using the native LAB Lactobacillus plantarum, isolated from a Colombian biorefinery. The effect of batch and continuous fed-batch at the bioreactor scale were also evaluated. Fermentation conditions were 37 °C, 150 rpm and pH 5.8, controlled with NH5CO3. Samples were taken every 4 h to determine substrate consumption, cell population behavior (CFU/mL) and lactic acid (LA) production; all experiments were performed in duplicate. Lactobacillus plantarum showed a growth rate µ=0.56 h-1 and a doubling time of 1.22 h. Likewise, its fermentation performance achieved productions of 50 and 107.3 g/L of lactic acid and yields of Yp/s 82.7 and 94 % in the batch and fed-batch strategies, respectively. The results show that the culture medium using industrial co-products provided the necessary nutritional requirements to the native strain and, together with an adequate continuous fed-batch fermentation strategy, resulted in an increase of 13.7 % in the yield of lactic acid, a basic pillar in the development of an economic and sustainable system.