Combination of ARTP mutagenesis and color-mediated high-throughput screening to enhance 1-naphthol yield from microbial oxidation of naphthalene in aqueous system

摘要

Strain QCG of the aerobic bacteria Bacillus cereus is capable of producing 1 -naphthol from naphthalene, this strain was first isolated and characterized in this study. Strain QCG was mutagenized to enhance 1 -naphthol production, using atmospheric and room temperature plasma (ARTP) technology. Then, a microbial clone screening system was used to accelerate the operation. Meanwhile, a novel color-mediated high-throughput screening using 4-aminoantipyrine was performed to screen mutants. The optimal mutant strain QCG4 produced 19.58±0.34 mg·L~(-1) 1-naphthol from naphthalene that was 47.32% higher than that of the original strain (13.29±0.28 mg • L~(-1)). In addition, the optimal conditions for 1 -naphthol production via whole-cell catalysis of strain QCG4 were determined to be an OD_(600) of 40, 150 mg • L~(-1) naphthalene, and 7.5% dimethyl formamide as a co-solvent at pH 7.5 and 26°C for 3 h, resulting in 41.18±0.12 mg·L~(-1) 1-naphthol, i.e., the mutant strain produces a 2.1-fold higher yield compared to the original strain.