Characterization of an inhibitor-resistant endo-1,4-ß-mannanase from the gut microflora metagenome of Hermetia illucens.
Biotechnol Lett
; 40(9-10): 1377-1387, 2018 Oct.
Article
em En
| MEDLINE
| ID: mdl-30078113
ABSTRACT
OBJECTIVE:
Hermetia illucens is a voracious insect scavenger that efficiently decomposes food waste. To exploit novel hydrolytic enzymes from this insect, we constructed a fosmid metagenome library using unculturable H. illucens intestinal microorganisms.RESULTS:
Functional screening of the library on carboxymethyl cellulose plates identified a fosmid clone with a product displaying hydrolytic activity. Fosmid sequence analysis revealed a novel mannan-degrading gene (ManEM17) composed of 1371 base pairs, encoding 456 amino acids with a deduced 54 amino acid N-terminal signal peptide sequence. Conceptual translation and domain analysis revealed that sequence homology was highest (46%) with endo-1,4-ß-mannosidase of Anaerophaga thermohalophila. Phylogenetic and domain analysis indicated that ManEM17 belongs to a novel ß-mannanase containing a glycoside hydrolase family 26 domain. The recombinant protein (rManEM17) was expressed in Escherichia coli, exhibiting the highest activity at 55 °C and pH 6.5. The protein hydrolyzed substrates with ß-1,4-glycosidic mannoses; maximum specific activity (5467 U mg-1) occurred toward locust bean gum galactomannan. However, rManEM17 did not hydrolyze p-Nitrophenyl-ß-pyranosides, demonstrating endo-form mannanase activity. Furthermore, rManEM17 was highly stable under stringent conditions, including polar organic solvents as well as chemical reducing and denaturing reagents.CONCLUSIONS:
ManEM17 is an attractive candidate for mannan degradation under the high-organic-solvent and protein-denaturing processes in food and feed industries.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Beta-Manosidase
/
Dípteros
/
Metagenoma
/
Microbioma Gastrointestinal
Limite:
Animals
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article