title: Multiple Genes in a Single Host: Cost-Effective Production of Bacterial Laccase (cotA), Pectate Lyase (pel), and Endoxylanase (xyl) by Simultaneous Expression and Cloning in Single Vector in E. coli.
abstract: This study attempted to reduce the enzyme production cost for exploiting lignocellulosic materials by expression of multiple genes in a single host. Genes for bacterial laccase (CotA), pectate lyase (Pel) and endoxylanase (Xyl), which hold significance in lignocellulose degradation, were cloned in pETDuet-1 vector containing two independent cloning sites (MCS). CotA and xyl genes were cloned in MCS1 and MCS 2, respectively. Pel gene was cloned by inserting complete cassette (T7 promoter, ribosome binding site, pel gene, His tag and complete gene ORF) preceded by cotA open reading frame in the MCS1. IPTG induction of CPXpDuet-1 construct in E. coli BL21(DE3) resulted in expression of all three heterologous proteins of ~65 kDa (CotA), ~45 kDa (Pel) and ~25 kDa (Xyl), confirmed by SDS-PAGE and western blotting. Significant portions of the enzymes were also found in culture supernatant (~16, ~720 and ~370 IU/ml activities of CotA, Pel and Xyl, respectively). Culture media optimization resulted in 2, 3 and 7 fold increased secretion of recombinant CotA, Pel and Xyl, respectively. Bioreactor level optimization of the recombinant cocktail expression resulted in production of 19 g/L dry cell biomass at OD600nm 74 from 1 L induced culture after 15 h of cultivation, from which 9, 627 and 1090 IU/ml secretory enzyme activities of CotA, Xyl and Pel were obtained, respectively. The cocktail was also found to increase the saccharification of orange peel in comparison to the xylanase alone. Thus, simultaneous expression as well as extra cellular secretion of these enzymes as cocktail can reduce the enzyme production cost which increases their applicability specially for exploiting lignocellulosic materials for their conversion to value added products like alcohol and animal feed.
authors.affiliation: Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South campus, Benito Juarez Road, New Delhi, 110021, India.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South campus, Benito Juarez Road, New Delhi, 110021, India.
authors.forename: Kavish Kumar
authors.initials: KK
authors.lastname: Jain
authors.affiliation: Uttarakhand State Council of Science and Technology [UCOST], Vigyan Dham, Post Office- Jhajra, Dehradun, Uttarakhand, 248007, India.
authors.forename: Kailash N
authors.initials: KN
authors.lastname: Bhardwaj
authors.affiliation: Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South campus, Benito Juarez Road, New Delhi, 110021, India.
authors.forename: Subhojit
authors.initials: S
authors.lastname: Chakraborty
authors.affiliation: Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South campus, Benito Juarez Road, New Delhi, 110021, India.|Central University of Haryana, Jant-Pali Village, Mahendergarh District, Pali, Haryana, 123029, India.
authors.forename: Ramesh Chander
authors.initials: RC
authors.lastname: Kuhad
mesh_terms: D003001:Cloning, Molecular; D043364:Endo-1,4-beta Xylanases / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D005822:Genetic Vectors; D042845:Laccase / Q000235:genetics / Q000378:metabolism*; D016366:Open Reading Frames; D011133:Polysaccharide-Lyases / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D042845:Laccase; D043364:Endo-1,4-beta Xylanases; D011133:Polysaccharide-Lyases; C023911:pectate lyase