D-lactate production from Spirulina (Arthrospira platensis) biomass using lactogenic Escherichia coli

Biomass of Arthrospira platensis was investigated as a raw material for D-lactic acid (D-LA) production through a sequential saccharification and fermentation process with hydrolases (amylase, glucoamylase, and cellulase) and the lactogenic Escherichia coli strain JU15. The study was performed with an initial 10% load (w/w) of dry A. platensis, containing 35% of total carbohydrate. Enzymatic saccharification was carried out in two steps, first with an α-amylase and glucoamylase blend and then with a cellulase cocktail to release the glucose. After enzymatic saccharification (40 h), approximately 30 g L−1 of glucose were released. These hydrolysates were converted with D-lactogenic E. coli JU15, producing 25.5 g L−1 D-lactate, which reached 86% of the theoretical conversion of glucose to lactate after only 9 h of fermentation and 0.255 gD-LA g−1 of dried A. platensis biomass. © 2020 Elsevier Ltd