Influence of Organic Solvents on Catalytic Behaviors and Cell Morphology of Whole-Cell Biocatalysts for Synthesis of 5′-Arabinocytosine Laurate

Abstract

A whole-cell based method was developed for the regioselective synthesis of arabinocytosine laurate. Among the seven kinds of bacteria strains tested in the acylation reaction, Pseudomonas fluorescens gave the highest productivity and a higher 5′-regioselectivity than 99%. Compared with pure organic solvents, the use of organic solvent mixtures greatly promoted the yield of the whole-cell catalyzed reaction, but showed little influence on the 5′-regioselectivity. Of all the tested solvent mixtures, the best reaction result was found in isopropyl ether/pyridine followed by isopentanol/pyridine. However, the whole-cells showed much lower thermostability in isopropyl ether/pyridine than in THF-pyridine. To better understand the toxic effects of the organic solvents on P. fluorescens whole-cells and growing cells were further examined. Significant influences of organic solvents on the biomass of the cells were found, which differed depending on the type of solvents used. SEM analysis visually revealed the changes in the surface morphology of whole-cells and growing cells cultured in media containing various organic solvents, in terms of surface smoothness, bulges and changed cell sizes. Results demonstrated that organic toxicity to cell structure played an important role in whole-cell mediated catalysis.

Simple and Rapid Screening Test to Detect Fake Honey Product

“…The precipitation of protein and other insoluble matters by RapidRAW reagent is a result of organic The reagent is designed based on previous studies about solvents effect on enzyme and cell structure where dehydration caused by solvents was reported as the main process contributing to cell disruption [18,19]. However, the reagent capacity is currently unable to differentiate 100% pure honey with low percentage of adulterated honey or contaminated pure honey.…”

Efficacy of ionic liquids on the growth and simultaneous xylanase production by Sporotrichum thermophile: membrane integrity, composition and morphological investigation

“…The resultant adapted culture contained xylanase activity of 25 U mL À1 . The nonadapted culture (not exposed to any ILs) also harvested at its log phase contained xylanase activity of 55 U mL C with addition of non-adapted cell extract for 48 h at 40 C.…”

“…[41][42][43] Solvents are reported to damage the integrity of cellular membranes thereby causing changes in permeability. 40,44 The extreme shrinkage and shrivelled appearance of the cellular structure may possibly be due to the leakage of the intracellular components. The SEM images showed that the IL [BMIM] [BF 4 ] is toxic and damaging to S. thermophile cells.…”

Immobilization of Ulp1 protease on NHS-activated Sepharose: a useful tool for cleavage of the SUMO tag of recombinant proteins

“…2b) and found both free and immobilized Ulp1 work well when ethanol was up to 20% (v/v). Stability in these solvents indicates that DMSO or ethanol can be added to minimize bacterial growth and be useful for some catalyzing and modification reactions (Yang et al 2014). Interestingly, SUMO was degraded when no DMSO was added while no perspective degradation existed after 10% DMSO was added ( Supplementary Fig.…”