Clostridium strain selection for co-culture with Bacillus subtilis for butanol production from agave hydrolysates

In this work, three Clostridium strains were tested for butanol production from Agave lechuguilla hydrolysates to select one for co-culturing. The agave hydrolysates medium was supplemented with nutrients and reducing agents to promote anaerobiosis. Clostridium acetobutylicum ATCC 824 had the highest butanol production (6.04 g/L) and was selected for further analyses. In the co-culture process, Bacillus subtilis CDBB 555 was used to deplete oxygen and achieve anaerobic conditions required for butanol production. The co-culture was prepared with C. acetobutylicum and B. subtilis without anaerobic pretreatment. Butanol production in co-culture from agave hydrolysates was compared with experiments using synthetic medium with glucose and a pure culture of C. acetobutylicum. The maximum butanol concentration obtained was 8.28 g/L in the co-cultured hydrolysate medium. Results obtained in the present work demonstrated that agave hydrolysates have the potential for butanol production using a co-culture of B. subtilis and C. acetobutylicum without anaerobic pretreatment.