Characterization of a processive inulosucrase from Lactobacillus mulieris for efficient biosynthesis of high-molecular-weight inulin

• Published in: Enzyme and microbial technology 2023-03, Vol.164, p.110186-110186, Article 110186
• Main Authors: Zhang, Shuqi, Ni, Dawei, Xu, Wei, Zhang, Wenli, Mu, Wanmeng
• Format: Article
• Language: English
• Subjects: Enzymatic properties; Inulin - biosynthesis; Inulosucrase; Lactobacillus - enzymology; Lactobacillus - genetics; Microbial inulin; Molecular Weight; Oligosaccharides; Processive transfructosylation; Sucrose - chemistry
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/j.enzmictec.2022.110186

Inulin has been determined to have many exceptional properties and functions and has been used in the food and pharmaceutical fields. Recently, microbial high-molecular-weight inulin synthesized from sucrose by inulosucrase attracted much attention. In this study, a novel inulosucrase from Lactobacillus mulieris was constructed, overexpressed, purified, and identified. The recombinant enzyme displayed the maximum activity at pH 6.0 and 55 °C, and it exhibited high thermostability below 45 °C. After optimizing the production conditions, the conversion rate from 100 g/L sucrose to inulin reached 31 %, meanwhile, the maximum molecular weight of produced inulin reached 3.21 × 106 g/mol. The truncated IS showed a “processive” transfructosylation process, only synthesizing a small number of short-chain oligosaccharides with polymerization degrees below 6, which was in favor of the accumulation of high-molecular-weight inulin. Given this, L. mulieris inulosucrase might be a good potential candidate for the industrial production of high-molecular-weight inulin. [Display omitted] •A novel inulosucrase from Lactobacillus mulieris UMB7800 was identified.•Reaction conditions were optimized to get high inulin production and molecular weight.•The maximum molecular weight of produced inulin reached 3.21 × 106 g/mol.•The enzyme showed a “processive” transfructosylation process.