Structure and composition analysis of clostridium acetobutylicum biofilm

Clostridium acetobutylicum(C. acetobutylicum) can be immobilized on fiber carriersand form biofilm (BF). It is important to study BF structure and composition in order to apply BF into fermentation and improve fermentation performance. Electron microscopic analysis shows that a three-dimensional network structure is formed via C. acetobutylicum cells adsorption, aggregation, accumulation and wrapped up by extracellular matrix (EPS). The result indicates that the biofilm of C. acetobutylicum is made up of microbial cells and EPS after enzyme degradation. EPS contains extracellular proteins, polysaccharides (main support structure), nucleic acids and lipids. The cell content is 2.26%~3.38% when considering linear relationship between cell number and dry weight. After specific biological and chemical analysis of BF composition, it is found that polysaccharide is the most abundant chemical in BF dry weight (36.09%), and protein, nucleic acids and lipids accounted for 23.86%, 4.05% and 10.85%, respectively.