Lipase production by Acinetobacter radioresistens in the presence of a nonwoven fabric

Lipase production by Acinetobacter radioresistens was performed in a 2-L tank fermentor equipped with a nonwoven fabric, which was made of nylon 6 fiber and coated with a hydrophobic acrylic resin. The fermentation medium contained 2% (v/v) n-hexadecane as the carbon source. The use of the nonwoven fabric was intended for the dispersion of hydrocarbons; thus, the contact surface for the cells to assimilate n-hexadecane can be increased without using emulsifiers. The formation of lipase was found to be growth-associated when the cells grew on n-hexadecane. The use of the nonwoven fabric increased the lipase yield by 130%. Further supplementation of 0.1% (v/v) olive oil to the medium could markedly shorten the fermentation time, and thus increase the volumetric productivity. The use of the nonwoven fabric offered two additional advantages in the lipase fermentation: ease of foam control and favorable partition of lipase in the aqueous phase.