Screening, Cloning, Enzymatic Properties of A Novel Thermostable Cellulase Enzyme and Its Potential Application on Water Hyacinth Utilization

Abstract

Cellulose is the cheapest, natural, renewable organic substance that is used as a carbon source in various fields. Water hyacinth, an aquatic plant rich in cellulose, is often used as a raw material in fuel production. However, natural cellulase can be hardly used in industrial production on account of its low thermal stability and activity. In this study, a metagenomic library was constructed. Then a new cellulase gene, cel1029, was screened by Congo red staining and expressed in the prokaryotic system. Enzymatic properties of Cel1029 were explored, including optimum temperature and pH, thermal and pH stability, and tolerance against organic solvents, metal ions and salt solutions. Finally, its ability of degrading water hyacinth was identified and evaluated. Cel1029 displayed high homology with endoglucanase in the glycoside hydrolase family 5 (GH5) and had high stability across a broad temperature range. More than 86% of its enzymatic activities were retained between 4 and 60°C after 24 h of incubation. Single-factor analysis and orthogonal design were further conducted to determine the optimal conditions for the highest reducing sugar yield of water hyacinth. Interestingly, Cel1029 efficiently transformed water hyacinth with a reducing sugar yield of 430.39 mg/g in 22 h. These findings may open the door for significant industrial applications of a novel GH5 cellulase (NCBI Reference Sequence: MK051001, Cel1029) and help identify more efficient methods to degrade cellulose-rich plants.

Cloning of cellulase gene using metagenomic approach of soils collected from Wadi El Natrun, an extremophilic desert valley in Egypt

“…Cellulose is the most cost-effective, natural, and renewable organic compound used as a carbon source in an assortment of solicitations [ 1 ]. The much more common carbohydrate on the planet is cellulose.…”

Characterization of a novel thermophilic metagenomic GH5 endoglucanase heterologously expressed in Escherichia coli and Saccharomyces cerevisiae

“…As with many extremophilic microorganisms, thermophiles are difficult to grow in laboratory conditions and culture independent methods such as metagenomics are needed for assessing their metabolic potential [15]. Lists of thermophilic cellulases found by metagenomics [12] and characterized thermophilic cellulases [3] are available, and novel cellulases found following this strategy continue to be discovered [16,17] showing the interest for these biocatalysts. Moreover, the discovery of multifunctional enzymes that can act on more than one biomass polymer [18][19][20], and the characterization of microbial consortiums that produce multiple lignocellulolytic enzymes [21] are also recent research focuses.…”

Study on mechanism of wheat straw lignin degradation by lignin peroxidase from Irpex lacteus

“…infrared techniques are well suited to detect changes in molecular structure and chemical components and are therefore widely used in the analysis of lignin degradation products (Jong et al 2017a;Rai et al 2018a; Zhao et al 2021a); Sun et al (Daochen et al 2018a) summarized the key functional group changes before and after enzymatic hydrolysis of lignocellulose, and to provide a reference for analyzing the functional group changes of products. GC-MS is one of the most effective ways to determine unknown compounds and their structures (Zhu et al 2020b;2021).…”