Evaluation of cellulolytic fungal-bacterial biofilms for the enhancement of bioethanol production

Biodegradation of lignocellulosic materials by cellulolytic microbial consortia would be beneficial in cellulosic biofuel production. This study aimed at investigating the cellulose degradation potential of fungal-bacterial biofilms (FBBs) followed by bioethanol production. Fungi and bacteria were isolated from soil samples and their cellulolytic activity was analyzed in carboxy methylcellulose medium. FBBs were developed from the selected fungi and bacteria and their cellulolytic activity was evaluated using reducing sugar production through 3,5-Dinitro Salicylic acid method. Cellulolytic digestion followed by fermentation was performed with the selected biofilms by co-culturing Saccharomyces cerevisiae suspension. Ethanol content was quantified by dichromate method and confirmed through FTIR analysis. The highest significant (P < 0.05) cellulolytic activity was observed in Aspergillus niger (F6) and Pseudomonas aeruginosa (B7). Significantly (P < 0.05) the highest cellulolytic activity was recorded by A. niger-P. aeruginosa biofilm (FB2). Fermentation study confirmed higher production of ethanol by the biofilms co-cultured with S. cerevisiae over their single cultures and the highest was recorded by A. niger - Bacillus subtilis biofilm (FB1) co-cultured with S. cerevisiae. In this context, FBB can be considered as an important agent for bioethanol production from cellulosic materials through cellulolytic digestion followed by fermentation.