Engineering Escherichia coli biofilm to increase contact surface for shikimate and L-malate production

Qiang Ding,Jian Chen,Wei Chen,Cong Gao,Guipeng Hu,Liang Guo,Xiulai Chen,Yadi Liu,Liming Liu

doi:10.1186/s40643-021-00470-7

Qiang Ding, Jian Chen + Show 7 more

Open Access

https://doi.org/10.1186/s40643-021-00470-7

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Abstract

Microbial organelles are a promising model to promote cellular functions for the production of high-value chemicals. However, the concentrations of enzymes and nanoparticles are limited by the contact surface in single Escherichia coli cells. Herein, the definition of contact surface is to improve the amylase and CdS nanoparticles concentration for enhancing the substrate starch and cofactor NADH utilization. In this study, two biofilm-based strategies were developed to improve the contact surface for the production of shikimate and L-malate. First, the contact surface of E. coli was improved by amylase self-assembly with a blue light-inducible biofilm-based SpyTag/SpyCatcher system. This system increased the glucose concentration by 20.7% and the starch-based shikimate titer to 50.96 g L−1, which showed the highest titer with starch as substrate. Then, the contact surface of E. coli was improved using a biofilm-based CdS-biohybrid system by light-driven system, which improved the NADH concentration by 83.3% and increased the NADH-dependent L-malate titer to 45.93 g L−1. Thus, the biofilm-based strategies can regulate cellular functions to increase the efficiency of microbial cell factories based on the optogenetics, light-driven, and metabolic engineering.Graphical

Highlights

Microbial cell factories can utilize reproducible substances in a promising, alternative, and environmentally friendly manner for the production of high-valuable and green chemicals, including food additives, advanced biofuels, and fine pharmaceuticals (Choi et al 2019; Ko et al 2020; Lee and Kim 2015; Nielsen and Keasling 2016)
Screening of E. coli biofilm genes To obtain an available and controllable biofilm system, the five genes involved in E. coli biofilm formation were screened to obtain the biofilm
To confirm the controllability of E. coli biofilm formation, csgA was controlled by promoters with different strengths, resulting in differences in the amount of bound Congo red

Summary

Introduction

Microbial cell factories can utilize reproducible substances in a promising, alternative, and environmentally friendly manner for the production of high-valuable and green chemicals, including food additives, advanced biofuels, and fine pharmaceuticals (Choi et al 2019; Ko et al 2020; Lee and Kim 2015; Nielsen and Keasling 2016). Organelles could increase the efficiency of microbial cell factories at the cellular level by compartmentalizing key enzymes into targeted sub-organelles to improve enzymatic reaction efficiencies (Hammer and Avalos 2017). To increase the enzymatic reaction efficiency by using sub-organelles, various strategies have been utilized, including extracellular organelles, in which transport proteins regulate the movement of substances across the cell wall by rewiring functional membrane microdomains or vesicles (Dueber et al 2009; Sandoval and Papoutsakis 2016; Yang et al 2021); intracellular organelles, including mitochondria, peroxisomes, and endoplasmic reticulum, to improve intermediate product concentrations and accelerate enzymatic reactions (Avalos et al 2013) (DeLoache et al 2016; Grewal et al 2020); and artificial organelles, such as phase-separated droplets engineered to increase the transformation efficiency by concentrating key pathway enzymes into a compartment (Castellana et al 2014; Kuska and O’Reilly 2020; Zhao et al 2019). Chemical biosynthesis by Escherichia coli, Pseudomonas putida, or Bacillus subtilis could be effectively improved by using biofilms to regulate the contact surface, thereby improving the enzymatic reaction efficiency and chemical production (Benedetti et al 2016; Leonov et al 2021; Nguyen et al 2014)

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