title: Ultrasonication and steam-explosion as chitin pretreatments for chitin oligosaccharide production by chitinases of Lecanicillium lecanii.
abstract: In this study, chitin oligosaccharides have been successfully produced using chitinases from submerged fermentation of Lecanicillium lecanii. The highest Hex, Chit and Prot production was 0.14, 0.26 and 2.05 U/mg of protein, respectively, which were attained varying pH from 5 to 8 after 96 h. Culture conditions conducted at constant pH of 6 resulted in significantly lower enzyme production. The crude enzyme was partially purified by salting out with (NH4)2SO4 followed by size exclusion chromatography to isolate the chitinase mixture for further chitin hydrolysis assays. In this regard, chitin substrates were pretreated with sonication and steam explosion prior to enzymatic reaction. Structural changes were observed with steam explosion with 11.28% reduction of the crystallinity index attained with the lowest chitin/water ratio (0.1g/mL). Pretreated chitins reached the highest production of reducing sugars (0.37 mg/mL) and GlcNAc (0.59 mg/mL) in 23.6% yield.
authors.affiliation: Universidad Autonoma Metropolitana, Departamento de Biotecnologia, Laboratorio de Biopolimeros, San Rafael Atlixco 186, Mexico City C.P. 09340, Mexico.
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Villa-Lerma
authors.affiliation: Universidad Autonoma Metropolitana, Departamento de Biotecnologia, Laboratorio de Biopolimeros, San Rafael Atlixco 186, Mexico City C.P. 09340, Mexico.
authors.forename: Humberto
authors.initials: H
authors.lastname: González-Márquez
authors.affiliation: Universidad Nacional Autonoma de Mexico, Facultad de Quimica, Mexico City C.P. 04510, Mexico.
authors.forename: Miquel
authors.initials: M
authors.lastname: Gimeno
authors.affiliation: Universidad Autonoma Metropolitana, Departamento de Biotecnologia, Laboratorio de Biopolimeros, San Rafael Atlixco 186, Mexico City C.P. 09340, Mexico.
authors.forename: Alberto
authors.initials: A
authors.lastname: López-Luna
authors.affiliation: Universidad Nacional Autonoma de Mexico, Facultad de Quimica, Mexico City C.P. 04510, Mexico.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Bárzana
authors.affiliation: Universidad Autonoma Metropolitana, Departamento de Biotecnologia, Laboratorio de Biopolimeros, San Rafael Atlixco 186, Mexico City C.P. 09340, Mexico. Electronic address: smk@xanum.uam.mx.
authors.forename: Keiko
authors.initials: K
authors.lastname: Shirai
mesh_terms: D002241:Carbohydrates / Q000737:chemistry; D002686:Chitin / Q000096:biosynthesis*; D002688:Chitinases / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*; D003460:Crystallization; D004798:Enzymes / Q000737:chemistry; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D006999:Hypocreales / Q000201:enzymology*; D009844:Oligosaccharides / Q000096:biosynthesis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013227:Steam; D013696:Temperature; D013997:Time Factors; D014465:Ultrasonics
chemical_list: D002241:Carbohydrates; D004798:Enzymes; D009844:Oligosaccharides; D013227:Steam; D002686:Chitin; D048271:Chitosan; D002688:Chitinases
keywords: Chitin; Chitinases; Lecanicillium lecanii; Steam explosion