Boosting secretion of starch-converting enzymes from Priestia koreensis HL12 and its application in non-thermal cassava pulp saccharification process for maltooligosaccharides synthesis.

Abstract

Exploring novel amylolytic enzymes and understanding their biochemical properties are essential for advancing starch-based industries. This study focused on identifying the effective extracellular enzymes produced by Priestia koreensis HL12, a novel starch-converting bacterium, through a combined proteomics and genomics approach. Genome annotation revealed 82 genes belonging to various CAZyme families. Among the ten media tested for amylolytic enzyme production, raw cassava pulp was identified as the most effective carbon source, yielding a remarkable starch-degrading activity of 452.6 ± 2.944 U/mg protein against cassava starch. The extracellular enzymes demonstrated significant potential for high-solid enzymatic hydrolysis of raw cassava pulp (5% w/v), achieving a conversion rate of 72% (719.1 mg/g biomass) at 45 °C, pH 5.0 for 24 h of hydrolysis. Proteomics analysis provided insights into the specific enzymes responsible for efficient starch breakdown and modification. These findings position P. koreensis HL12 as a highly effective bacterium for cellulase/xylanase-free amylase production. This work not only highlights the unique enzymatic profile of P. koreensis HL12 but also emphasizes its significant role in optimizing starch bioconversion processes, ultimately contributing to the development of more sustainable biorefineries.