Insights into Bacterial Cellulose Biosynthesis from Different Carbon Sources and the Associated Biochemical Transformation Pathways in Komagataeibacter sp. W1.

Shan-Shan Wang,Jia-Lian Chen,Deng-Long Chen,Da-Chun Zhang,Min Li,Xiao-Xia Shi,Yong-He Han,Yu-Xuan Ye

doi:10.3390/polym10090963

Abstract

Cellulose is the most abundant and widely used biopolymer on earth and can be produced by both plants and micro-organisms. Among bacterial cellulose (BC)-producing bacteria, the strains in genus Komagataeibacter have attracted wide attention due to their particular ability in furthering BC production. Our previous study reported a new strain of genus Komagataeibacter from a vinegar factory. To evaluate its capacity for BC production from different carbon sources, the present study subjected the strain to media spiked with 2% acetate, ethanol, fructose, glucose, lactose, mannitol or sucrose. Then the BC productivity, BC characteristics and biochemical transformation pathways of various carbon sources were fully investigated. After 14 days of incubation, strain W1 produced 0.040–1.529 g L−1 BC, the highest yield being observed in fructose. Unlike BC yields, the morphology and microfibrils of BCs from different carbon sources were similar, with an average diameter of 35–50 nm. X-ray diffraction analysis showed that all membranes produced from various carbon sources had 1–3 typical diffraction peaks, and the highest crystallinity (i.e., 90%) was found for BC produced from mannitol. Similarly, several typical spectra bands obtained by Fourier transform infrared spectroscopy were similar for the BCs produced from different carbon sources, as was the Iα fraction. The genome annotation and Kyoto Encyclopedia of Genes and Genomes analysis revealed that the biochemical transformation pathways associated with the utilization of and BC production from fructose, glucose, glycerol, and mannitol were found in strain W1, but this was not the case for other carbon sources. Our data provides suggestions for further investigations of strain W1 to produce BC by using low molecular weight sugars and gives clues to understand how this strain produces BC based on metabolic pathway analysis.

Highlights

Cellulose is the most abundant and widely used biopolymer on earth, most of which is produced by plants [1,2]
Production has been hardly reported [16]. Both ethanol and acetate are spiked in media to enhance bacterial cellulose (BC) production by improving adenosine triphosphate (ATP) production, which is responsible for energy supply in the tricarboxylic acid (TCA) cycle and sugar metabolisms
To evaluate the BC productivities in the media spiked with different carbon sources, glucose in HS medium was replaced with acetate (C2 H4 O2 ), ethanol (C2 H6 O), fructose (C6 H12 O6 ), glycerol (C3 H8 O3 ), lactose (C12 H22 O11 ), mannitol (C6 H14 O6 ), and sucrose (C12 H22 O11 ), respectively

Summary

Introduction

Cellulose is the most abundant and widely used biopolymer on earth, most of which is produced by plants [1,2]. Four strains of Komagataeibacter xylinus studied by Singhsa et al [12] showed great ability for BC production on using fructose, lactose, maltitol, sucralose, and xylitol Other substrates such as glycerol, sucrose, and galactose are good carbon sources for BC production [13,14,15]. Unlike sugars or their derivatives, using ethanol and acetate as the substrates for BC production has been hardly reported [16] More often, both ethanol and acetate are spiked in media to enhance BC production by improving adenosine triphosphate (ATP) production, which is responsible for energy supply in the tricarboxylic acid (TCA) cycle and sugar metabolisms. These processes are achieved by promoting the activities of glucokinase and fructokinase for BC production and inhibiting the activities of gluconokinase and glucose-6-phosphate dehydrogenase in pentose phosphate metabolism for energy production [17,18,19,20,21,22]

Methods

Results

Conclusion