RESUMO

A new xylanolytic strain, Paenibacillus favisporus CC02-N2, was isolated from sugarcane plantation fields in Brazil. The strain had a xylan-degrading system with multiple enzymes, one of which, xylanase Xyn30A, was identified and characterized. The enzyme is a single-domain xylanase belonging to family 30 of the glycosyl hydrolases (GH30). Xyn30A shows high activity on glucuronoxylans, with a Vmax of 267.2 U mg⁻¹, a Km of 4.0 mg/ml, and a kcat of 13,333 min⁻¹ on beechwood xylan, but it does not hydrolyze arabinoxylans. The three-dimensional structure of Xyn30A consists of a common (ß/α)8 barrel linked to a side-chain-associated ß-structure, similar to previously characterized GH30 xylanases. The hydrolysis products from glucuronoxylan were methylglucuronic-acid-substituted xylooligomers (acidic xylooligosaccharides). The enzyme bound to insoluble xylan but not to crystalline cellulose. Our results suggest a specific role for Xyn30A in xylan biodegradation in natural habitats. The enzyme is a good candidate for the production of tailored xylooligosaccharides for use in the food industry and in the biotechnological transformation of biomass.

Assuntos

Proteínas de Bactérias/metabolismo , Paenibacillus/enzimologia , Microbiologia do Solo , Xilosidases/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Brasil , Clonagem Molecular , Estabilidade Enzimática , Cinética , Dados de Sequência Molecular , Paenibacillus/química , Paenibacillus/genética , Paenibacillus/isolamento & purificação , Especificidade por Substrato , Xilosidases/química , Xilosidases/genética