An isolated cellulolytic Escherichia coli from bovine rumen produces ethanol and hydrogen from corn straw

Abstract

BackgroundLignocellulosic biomass is the most abundant resource on earth. Lignocellulose is mainly composed of cellulose, hemicelluloses, and lignin. The special construction of three kinds of constituents led to the prevention of effective degradation. The goal of this work was to investigate the great potentials of bovine rumen for novel cellulolytic bacterial isolation, which may be used for chemicals and biofuel production from lignocellulose.ResultsA cellulolytic strain, ZH-4, was isolated from Inner Mongolia bovine rumen. This strain was identified as Escherichia coli by morphological, physiological, and biochemical characteristics and 16S rDNA gene sequencing. The extracellular enzyme activity analysis showed that this strain produces extracellular cellulases with an exoglucanase activity of 9.13 IU, an endoglucanase activity of 5.31 IU, and a β-glucosidase activity of 7.27 IU at the pH 6.8. This strain was found to produce 0.36 g/L ethanol and 4.71 mL/g hydrogen from corn straw with cellulose degradation ratio of 14.30% and hemicellulose degradation ratio of 11.39%.ConclusionsIt is the first time that a cellulolytic E. coli was isolated and characterized form the bovine rumen. This provided a great opportunity for researchers to investigate the evolution mechanisms of the microorganisms in the rumen and provided great chance to produce biofuels and chemicals directly from engineered E. coli using consolidated bioprocess.

Isolation and identification of cellulolytic bacteria from gastrointestinal tract of Arabian horse and investigation of their effect on the nutritional value of wheat straw

“…In the study by Pang et al . (), an E. coli strain with cellulose‐ and hemicellulose‐degrading activity was isolated from Inner Mongolia bovine rumen.…”

“…Another isolated bacteria in this study was E. coli with CMC activity 2Á43 U ml À1 . In the study by Pang et al (2017), an E. coli strain with cellulose-and hemicellulose-degrading activity was isolated from Inner Mongolia bovine rumen. Compared to control, the disappeared DM of bacterial treatment shows bacterial growth and degradation of DM by these organisms.…”

“…However, using them is associated with some problems (Hendriks and Zeeman 2009;Agbor et al 2011) as they require complex material and have detriments such as secondary pollution. Recently the researches have focused on biological alternatives, especially since they are environmentally benign and widely acceptable (P erez et al 2002;S anchez 2009;Sharma and Arora 2013). One of the biological methods is to use micro-organisms including fungi and bacteria many of which had been found to degrade cellulose and other plant cell wall fibres.…”

A state-of-the-art review of biohydrogen producing from sewage sludge

“…Mechery et al isolated 12 bacterial strains from wastewater, namely Salmonella , Pseudomonas , Proteus , Klebsiella , and Providencia . Pang et al isolated an E. coli strain ZH‐4 from bovine rumen with a hydrogen yield of 4.71 mL/g from corn straw. Mishra et al screened a Bacillus anthracis strain PUNAJAN 1 from palm oil mill effluent sludge and the maximum hydrogen production was 2.42 mol H 2 /mol mannose.…”

Genome Editing for the Production of Natural Products in Escherichia coli

“…This has been explored from various angles, including the isolation of varieties and strains from the environment with acquired and evolved metabolic pathways. For example, a new E. coli strain (strain ZH‐4) was isolated from bovine rumen and is capable of cellulose utilization and degradation . As cellulosic wastes are a large, natural and renewable carbon source this shows potential for this metabolic adaption to serve as a genetic framework for further strain modifications .…”