Optimization of the Culture Conditions of Bacterial Strains (Escherichia coli LR0250096.1 and Pseudomonas aeruginosa CP031449.2) to Produce Lignin Peroxidase

Lignin, and its by-products in the effluent of most agrochemical-based industries like pulp and paper, increase environmental pollution. There is, therefore, an increasing demand to degrade lignin and its derivatives using bacteria-produced ligninolytic enzymes. This study focused on optimizing growth and lignin peroxidase production of ligninolytic potential bacterial strains (E. coli accession no: LR0250096.1 and P. aeruginosa accession no: CP031449.2) for the first time. A submerged fermentation process was used to simultaneously optimize growth and crude lignin peroxidase production using kraft lignin as the substrate. The E. coli and P. aeruginosa were separately cultured under different pH, temperature, lignin (substrate) concentration and incubation periods. It was observed that the enzyme production was growth dependent. The optimum conditions for E. coli were pH 7.5, temperature 30 °C and lignin concentration 1 g/L. For P. aeruginosa the best conditions were pH 6.5, temperature 40 °C and lignin concentration 1 g/L. The enzyme production peaked after 7 days of incubation for both organisms were 21.53 ± 3.11 mg/ml and 18.13 ± 2.1 mg/ml respectively. It is apparent that both E. coli (LR0250096.1) and P. aeruginosa (CP031449.2) are mesophiles bacteria. E. coli function best in alkaline pH while P. aeruginosa prefers a slightly acidic environment. Hence, they are promising candidates in the reduction of lignocellulosic wastes.