Establishing a Co-Culture System for Clostridium Cellulovorans and Clostridium Aceticum for High Efficiency Biomass Transformation

C4 bio-refinery, such as butyrate and butanol production, is currently a research hotspot. However, undesirable waste products including H₂ and CO₂ result in lower product yield and a waste of energy. Clostridium aceticum has the ability to convert H₂ and CO₂ to acetate, which can be assimilated by other clostridia strains through the reversible acetate kinase and phosphotransacetylase pathway. This study setup a co-cultural system for C. aceticum and C. cellulovorans. Together they can convert the cellulosic biomass to butyrate or even butanol if a metabolic engineered strain is used, with considerably higher yields. Based on DSMZ 520 medium for C. cellulovorans and DSMZ 135 acetobacterium medium for C. aceticum, the practical pH ranges were evaluated for both strains. The pH 7.0-7.5 was suitable for both strains. By mixing these media with various ratios, an optimized formulation was defined for the co-cultural system. The evaluation of co-culture was conducted using glucose as substrate. The conversion rate of glucose to final products has increased by 5-10%.