Search

With the advent of increasingly loose nanofiltration membranes for dye desalination, synthesis methods based on interfacial polymerization and bio-inspired materials such as polydopamine (pDA) have been investigated. However, the long polymerization time of pDA greatly limits the synthesis and application of fast dye/salt separation membranes. In this work, prebiotic chemistry-inspired aminomalononitrile (AMN) was used as a binder to co-deposit the Mannich reaction of tetrakis(hydroxymethyl)phosphonium chloride (THPC) and polyethyleneimine (PEI) to form the positively charged selective layer rapidly. The optimum membrane had a water permeance of 30.7 LMH bar

Rebaudioside A is an attractive non-nutritive natural sweetener. UDP-glycosyltransferase UGT76G1 from Stevia rebaudiana Bertoni has been found to effectively convert stevioside to rebaudioside A. In this study, sucrose synthase mbSUS from Vigna radiata was first reported to co-operate with glycosyltransferase. Compared with other sucrose synthases, mbSUS was selected for co-expression with UGT76G1 in Pichia pastoris GS115 because of its high efficiency in improving the synthesis of rebaudioside A. After optimizing the gene dose ratio of mbSUS and UGT76G1, which is an effective whole-cell biocatalyst GS115 (U76/mb3:1) was constructed. For the biosynthesis of rebaudioside A with whole-cell biocatalyst GS115 (U76/mb3:1), the reaction parameters were optimized and the limiting conditions were identified. Under optimal conditions, the yield of rebaudioside A reached 261.2 mM in a 1 L batch within 26 h. Based on its the high reaction efficiency, the whole-cell catalyst GS115 (U76/mb3:1) is a powerful biocatalyst with the potential for industrial-scale synthesis.