关键词: 苎麻脱胶；共生菌群；芽孢杆菌；分离；鉴定

Abstract:

In order to isolate high efficient degumming strains from a ramie retting bacterial consortium RAMCD407, a specific solid medium mainly consisted of ramie gum materials from ramie retting liquids by RAMCD407 was utilized for strain screening and isolating. Biochemical methods combined with 16S rRNA gene sequencing and morphological discrimination were chosen for strain identification. Enzyme activity analysis and practical degumming experiments were adopted to test the potential of selected strains in ramie degumming industries. Two strains designated K30 and L11 were obtained after purification and screening. Both 2 strains can form hydrolysis halos either on the plate containing pectin or xylan. The pectinase activities were 238.47 U/mL for K30 and 170.79 U/mL for L11. The xylanase activities were 98.36 U/mL for K30 and 64.11 U/mL for L11. The residual gum contents of ramie fibers were reduced from 32.3% to 12.43% and 15.70%, respectively and the breaking strength of ramie fibers was all more than 5.5 cN/dtex, when K30 and L11 were used in ramie retting practice. VITEK testing and 16S rDNA sequencing consistently showed that K30 shared a 99% similarity with Bacillus subtilis and L11 shared a 99% similarity with Bacillus cereus.

Key words: ramie degumming, bacteria consortium, Bacillaceae, isolation, identification