Exploitation of Food Feedstock and Waste for Production of Biobutanol

Nine strains of solventogenic clostridia including the species C. acetobutylicum, C. beijerinckii, C. pasteurianum, and C. saccharoperbutylacetonicum were tested for the solvents production using potato, maize, and sugar beet molasses as substrates. The solvent concentrations reached in the cultivations with maize and molasses media (15.23 g/l and 13.70 g/l, respectively) looked promising. Based on the screening experiments, the strain C. acetobutylicum DSM 1731 was selected for further experiments in the laboratory bioreactor using the maize medium. The results achieved in this batch cultivation (total solvents concentration 12.91 g/l, the yield from maize starch 22%, the solvents formation productivity 0.22 g/l/h, and the ratio of B:A:E approximately 2:1:0) imply the potential of maize as an energetic crop for the biofuel production. In addition, whey protein concentrate was tested as a possible replacement of the usual but expensive media components, i.e. yeast autolysate and/or trypton, and it was confirmed that these substitutes functioned well in the glucose medium.