Application of immobilized glycosidase in the synthesis of glycoside compounds / 生物工程学报

Glycoside compounds are widely used in medicine, food, surfactant, and cosmetics. The glycosidase-catalyzed synthesis of glycoside can be operated at mild reaction conditions with low material cost. The glycosidase-catalyzed processes include reverse hydrolysis and transglycosylation, appropriately reducing the water activity in both processes may effectively improve the catalytic efficiency of glucosidase. However, glucosidase is prone to be deactivated at low water activity. Thus, glucosidase was immobilized to maintain its activity in the low water activity environment, and even in neat organic solvent system. This article summarizes the advances in glycosidase immobilization in the past 30 years, including single or comprehensive immobilization techniques, and immobilization techniques combined with genetic engineering, with the aim to provide a reference for the synthesis of glycosides using immobilized glycosidases.

Application of sucrose phosphorylase in glycosylation / 生物工程学报

Water solubility, stability, and bioavailability, can be substantially improved after glycosylation. Glycosylation of bioactive compounds catalyzed by glycoside hydrolases (GHs) and glycosyltransferases (GTs) has become a research hotspot. Thanks to their rich sources and use of cheap glycosyl donors, GHs are advantageous in terms of scaled catalysis compared to GTs. Among GHs, sucrose phosphorylase has attracted extensive attentions in chemical engineering due to its prominent glycosylation activity as well as its acceptor promiscuity. This paper reviews the structure, catalytic characteristics, and directional redesign of sucrose phosphorylase. Meanwhile, glycosylation of diverse chemicals with sucrose phosphorylase and its coupling applications with other biocatalysts are summarized. Future research directions were also discussed based on the current research progress combined with our working experience.

Genome editing of industrial microorganism / 生物工程学报

Genome editing is defined as highly-effective and precise modification of cellular genome in a large scale. In recent years, such genome-editing methods have been rapidly developed in the field of industrial strain improvement. The quickly-updating methods thoroughly change the old mode of inefficient genetic modification, which is "one modification, one selection marker, and one target site". Highly-effective modification mode in genome editing have been developed including simultaneous modification of multiplex genes, highly-effective insertion, replacement, and deletion of target genes in the genome scale, cut-paste of a large DNA fragment. These new tools for microbial genome editing will certainly be applied widely, and increase the efficiency of industrial strain improvement, and promote the revolution of traditional fermentation industry and rapid development of novel industrial biotechnology like production of biofuel and biomaterial. The technological principle of these genome-editing methods and their applications were summarized in this review, which can benefit engineering and construction of industrial microorganism.

Optimization of cloning and expression of beta-glucanase gene from Bacillus amyloliquefaciens / 生物工程学报

To compare of performance of beta-1,3-1,4-glucanase gene (bgl) in different expression systems, the beta-1,3-1,4-glucanase gene (GenBank Accession No. EU623974) was amplified from Bacillus amyloliquefaciens BS5582 by PCR and was cloned into three vectors pEGX-4T-1, pET20b(+) and pET28a(+) to construct pEGX-4T-1-bgl, pET20b(+)-bgl and pET28a(+)-bgl recombinant plasmids. The pEGX-4T-1-bgl was transformed into three different Escherichia coli host strains. The pET20b (+)-bgl and pET28a (+)-bgl were transformed into E. coli BL21 (DE3) respectively. Recombinant beta-glucanase was expressed by IPTG inducement in these recombinants. E. coli BL21 (DE3)-pET28a (+)-bgl had the highest enzyme activity. In Luria-Bertani medium, the total enzyme activity was (322.0 +/- 8.8) U/mL, which was 40.1% of original strain in optimal shaking flask condition. This recombinant's performance was studied in Terrific Broth medium under inducement of IPTG and lactose at the same time., and the highest total enzyme activity could reach (1883.3 +/- 45.8) U/mL (818.8% of the original), which indicate that the recombinant strain has a good value in industry application.