酵素工学
オープンアクセス

概要

Optimization of Culture Conditions for Production of β-galactosidase from Lactobacillus acidophilus Isolated from Dairy Industrial Effluent

Oparaji EH, Okwuenu PC, Onosakponome I, Eze SOO, Chilaka FC

β-galactosidase producing Lactobacillus was isolated from dairy industrial waste water collected from Rumuekini, Rivers state. Standard microbiology, biochemical and molecular techniques (16s DNA sequencing) were used for confirmation of the bacterial strain as Lactobacillus acidophilus. Macfarlane solution was used for standardization of the microbial inoculum and determination of the heterotrophic counts. P-NPG served as the best substrate for β- galactosidase production from Lactobacillus acidophilus with rapid yellow colouration after two days of incubation. Submerged Fermentation (SMF) system was used for the enzyme production. Inoculum size of 2 ml with total heterotrophic counts of 5.4 × 10⁸ cfu/ml was used throughout the optimization studies. Carbon sources including: lactose, glucose, sugarcane baggase and combination of glucose and lactose were optimized, lactose was found suitable for the protein production with highest β-galactosidase activity (121.71 μmol/min). Among the nitrogen sources optimized, peptone was found optimal for β-galactosidase production with activity of 119.34 μmol/min. pH 6.0 was found the best for the enzyme production. Effect of incubation period on the enzyme production showed the 12th day of fermentation as the peak day for β-galactosidase production from Lactobacillus acidophilus. The results from this study have shown that Lactobacillus acidophilus isolated from dairy industrial waste water has the potential for β- galactosidase production in a commercial scale for both industrial and clinical applications.