Table 4 Biofilm formation characteristics of Clostridium acetobutylicum/C. beijerinckii onto various supports
Support | Characteristics |
|---|---|
Bonechar | C. acetobutylicum culture - Adsorption is quick - Biomass layers (biofilms) become visible in 3–4 days time - Between day 2 and 4, the culture produces polysaccharide in high concentrations (2.04 gL-1 broth as compared to 0.95 gL-1 broth from day 5 to 30) - Once initial layers appear, biomass accumulation is quick - Desorption does not occur at high dilution rates - < than 25% cells were desorbed when adsorbed cell particles were agitated at 200–300 rpm (in shake flasks on shaker) at pH 2.7 for 18–24 h at 30°C - During initial stages (2–4 days) the culture produced high concentrations of acids (~6–9 gL-1) followed by becoming solventogenic - During solventogenic stages fluctuations in solvent concentrations were less |
Glass beads | C. acetobutylicum culture - Biomass accumulation takes much longer than bone char - During initial stages (2–4 days) higher amount of polysaccharide production does not occur - Cells do not stick to the support as firmly as onto bonechar - Reactor produces <20% solvents as compared to bonechar adsorbed cells - Reactors are not stable as solvent concentration fluctuates - Cells can easily be washed off |
Glass wool, Polypropylene tow, and stainless steel wire balls | C. acetobutylicum culture - <20% biomass accumulated than in bonechar packed reactor - Cells do not stick to the support firmly and can be desorbed easily - Reactors are not stable and poor solventogenesis occurred |
Clay brick (Ref. 38) | C. beijerinckii culture - Cells stick firmly as in case of bonechar and reactors were solventogenic |