N-Terminal Fused Signal Peptide Prompted Extracellular Production of a Bacillus-Derived Alkaline and Thermo Stable Xylanase in E. coli Through Cell Autolysis

Zhang, Faying; He, Huahua; Deng, Ting; Ge, Haoran; Yu, Chan; Feng, Liang; Huang, Fenghong; Li, Yang

doi:10.1007/s12010-020-03323-9

Cited by 4 publications

(1 citation statement)

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“…The underlined RR-residues are essential for the protein export. The Tat signal peptides contain a positively charged N terminal region, a hydrophobic H region, and a polar C terminal region . The E.…”

Section: Introductionmentioning

confidence: 99%

One-Pot Biosynthesis of l-Aspartate from Maleic Anhydride via a Thermostable Dual-Enzyme System under High Temperature

liu

Zong

Wang

et al. 2022

J. Agric. Food Chem.

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l-Aspartate is an important chemical in the food and pharmaceutical industries. Herein, a dual-enzyme system was constructed to synthesize l-aspartate from maleic anhydride at 50 °C, which can reduce the byproduct production. Maleate transformed from maleic anhydride in the solution was converted into l-aspartate via fumarate catalyzed by maleate isomerase (MaiA) and thermostable aspartase (AspB), respectively. Because MaiA is a rate-limiting enzyme, enzyme activities of various MaiAs were compared, and the efficient and thermostable maleate isomerase AaMaiA from Alicyclobacillus acidoterrestris was chosen. The K cat/K m value of AaMaiA was 264.4 mM–1 min–1. AaMaiA and AspB were coexpressed in E. coli to produce l-aspartate. To improve the l-aspartate production rate, the ribosome binding site (RBS) sequence located upstream of AaMaiA was optimized and the Tat signal peptide was fused with AaMaiA. The conversion rate was 96% within 60 min, and the intermediate was not detected, the possible reason of which is that high temperature inhibits the activity of bacterial endogenous enzymes, but functional enzymes remain active. Cells from fermentation produced 243.6 g/L (1.83 M) of l-aspartate with a 2 M substrate. Our study revealed an effective method to produce l-aspartate without using gene knockout and provided a strategy for l-aspartate production in the industrial field.

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Section: Introductionmentioning

confidence: 99%