Heterologous production and secretion of active-form plant peroxidase in Brevibacillus choshinensis and their monolignol polymerization abilities analysis

Plant peroxidases are important for several processes, such as defense against pathogens, and auxin metabolism. In this study, we report the active production and secretion of plant peroxidase and mutated enzymes in the bacterium Brevibacillus choshinensis for the first time in the world. We introduced mutations into prxA3a , an anionic peroxidase gene of hybrid aspen, Populus × kitakamiensis , to substitute the amino acid residues at the surface of the protein and analyzed their modified substrate specificities. We have also reported heterologous expression of PrxA3a and mutated enzymes in yeast. Enzymes secreted in the culture medium by B . chosinensis were purified by Ni affinity chromatography, anion-exchange chromatography, and size-exclusion chromatography. The ability of the mutated enzymes to polymerize sinapyl alcohol, a monolignol, was higher than that of the wild-type enzyme. In particular, the FYAW-mutated enzyme produced by the bacterium showed higher polymerization activity, similar to that of the FYAW-mutated enzyme produced by yeast.