D-Lactic acid production from waste cardboard

The effects caused by alkaline treatment on the susceptibility of waste cardboard to enzymatic hydrolysis have been studied. Optimised conditions leading to extensive saccharification of both cellulose (870g kg(-1) conversion) and hemicelluloses (845g kg(-1) conversion) were identified. Samples treated under selected operational conditions were employed for producing D-lactic acid by simultaneous saccharification and fermentation (SSF) in media containing cellulases, beta-glucosidase and Lactobacillus coryniformis ssp torquens cells. SSF fed-batch experiments led to D-lactic acid concentrations up to 23.4 g dm(-3) at a product yield of 514g lactic acid kg(-1) of potential glucose and a volumetric productivity of 0.48g dm(-3) h(-1). (C) 2004 Society of Chemical Industry.