| Flax fiber is an important textile industrial material. Degumming is the key step in flax production because it effects the production cycle and fiber quality directly. The component of flax colloid is extremely complicated, mainly including pectin, hemicellulose and lignin. It has been widely researched on pectin and pectinase-producing microorganisms in biological-degumming field but the study on hemicellulose degradation is even rare. Mannan is main component in flax hemicellulose so mannanase is key degummase. Mannanase is an enzyme capable of hydrolyzing β-1,4-D-manno-pyanosyl linkages of mannan whose main product is manna-oligosaccharide. It has been widely used in nutritive, medical, textile, dyeing, oil extraction fields and so on.Two mannanase-producing bacterial strains, HDYM-03 and HDYM-04, were isolated from the fermentation liquid of flax retting. After identification of the two strains the fermentation conditions of them were optimized according to single factor and orthogonal tests.HDYM-03 was also applied to flax retting test. The results showed that:1. Both of the two strains were identified as Bacillus licheniformis according to the morphological, physiological, biochemical characteristics and the sequencing of 16S rDNA.2. The two strains grew best when cultured at 37℃ with 6% konjac powder as carbon, 3% peptone as nitrogen source, pH 8.0, 100mL medium per 250mL flask, incolumn volume for HDYM-03 was 2% and that for HDYM-04 was 1%. After 48 hours cultured, the two strains could respectively show the highest mannanase activity as 5122U/mL(HDYM-03) and 5168U/mL (HDYM-04)which were the highest values as far as now.3. HDYM-03 can also produce high activity of pectinase but can't produce cellulase so it does no harm to flax fiber. The retting test with... |
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