The Research Of The Predominant Strains Of Ramie Degumming Bacteiral Consortium RAMCD407

Ramie is the high-grade natural fiber material with Chinese characteristics, riching in resources, and its products of clothes and home textile obtain much favor of consumers at home and abroad. However, decorticated ramie fibers contain25-35%gum consisting mainly of pectin and hemicellulose, which, therefore, needs to be removed by the process of degumming as fully as possible to fulfill the textile requirement. As the conventional degumming process with a solution of NaOH not only has high consumption of chemicals and energy but also results in serious environmental pollution. Microbial technique of degumming is more eco-friendly, energy-saving as compared to the chemical process, and is widely regarded as the ramie cleaner production technology. The principle of the biological degumming of ramie is using microorganisms and their enzymes to break down gum layer which wrapping the ramie fiber, releasing the fiber. Screening of the new ramie biological degumming bacteria with wide enzyme system and high enzyme activity has been an important research direction.In this paper, we studied the predominant strains of degumming bacterial consortium RAMCD407, in order to select efficient degumming strains which can be applied to biological degumming of ramie.Firstly, using of hydrolysis halos produced by strains on the plate mainly consisted of ramie gum materials from ramie retting liquids by RAMCD407and the hydrolysis halos produced by strains on the plate used pectin and xylan as the sole carbon source, combined with the enzyme activity test, isolated and screened two degumming predominant strains called K30and L11. Both two strains can form hydrolysis halos either on the plate containing pectin or on the plate containing xylan. The pectinase activity was238.47U/mL for K30and170.79U/mL for L11. The xylanase activity was98.36U/mL for K30and64.11U/mL for L11.Secondly, using of orthogonal experiments and single factor experiments, the optimum culturing conditions for ramie degumming bacteria K30was identified as ramie soaking liquids culture medium, initial pH8.0, inoculate quantity10%, bath ratio1:10, fermentation temperature40℃, shaking table speed200r/min, and the optimum culturing conditions for ramie degumming bacteria L11was identified as ramie soaking liquids culture medium, initial pH=8.0, inoculate quantity10%, bath ratio1:10, fermentation temperature42℃shaking table speed150r/min. K30and L11used for degumming of ramie, can make the fiber residue gum rate reduced to11.21%and13.68%from32.3%, the fiber strength all more than5.5cN/dtex.Finally, through morphological discrimination, biochemical methods combined with16S rDNA sequencing molecular methods identified that K30was Bacillus subtilis, and L11was Bacillus cereus. Therefore, through the researching of the predominant strains of degummed ramie degumming bacterial consortium RAMCD407, we found that there were high efficient degumming strains such as Bacillus subtitles K30and Bacillus cereus L11in the ramie retting bacterial consortium RAMCD407, and had good development and application value. But their degumming capability far less than original bacterial consortium. Leaving the original ecological environment, the synergistic effect between species is not obvious. At the same time, it shows that the role of the other strains in the original bacterial consortium cannot be ignored.