Combination of ARTP mutagenesis and color-mediated highthroughput 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 l-naphthol from naphtha-lene,this strain was first isolated and characterized in this study.Strain QCG was mutagenized to enhance l-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土0.34 mg·L-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 l-naphthol production via whole-cell catalysis of strain QCG4 were determined to be an OD600 of40,150 mg.L I naphthalene,and 7.5%dimethyl formamide as a co-solvent at pH 7.5 and 26℃ for 3 h,resulting in 41.18士0.12 mg·L-l-naphthol,i.e.,the mutant strain produces a 2.1-fold higher yield compared to the original strain.