高产几丁质酶高温紫链霉菌的筛选和发酵条件优化

Screening of high chitinase-production strain,Streptomyces thermoviolaceus and optimization of fermentation condition

从土壤中筛选得到1株高产耐热几丁质酶的嗜热菌株Z16,对其进行鉴定及产酶发酵条件优化研究。采用分子生物学结合形态学方法鉴定该菌为高温紫链霉菌(Streptomyces thermoviolaceus)。通过发酵培养基组分及培养条件的优化,得到了最佳发酵产酶培养基:胶体几丁质5g/L,粉末几丁质10g/L,酵母浸粉1.25g/L,黄豆粉3.75g/L,吐温20 4g/L。最佳培养条件为:接种量5%,45℃培养60h。在优化后的发酵条件下,该菌株最大产酶水平达5.5U/mL,比优化前产酶量提高了4.2倍,较高的产酶量为进一步研究该菌所产几丁质酶的纯化和性质提供了基础。该菌具有较好的应用前景。

A thermophilic Streptomyces strain capable of secreting thermostable chitinase was isolated from soil sample, and its fermentation conditions for chitinase production were optimized. The strain was identified as Streptomyces thermoviolaceus based on its biochemical characteristics and 16S rDNA sequence. After optimizing its fermentation medium and fermentation conditions, the optimal medium was obtained as： colloidal chitin 5 g/L, chitin powder 10 g/L, yeast extracts 1.25 g/L, soybean power 3.75 g/L, Tween 20 4 g/L, and the optimum fermentation condition was 45 ℃ and cultured for 60 h with 5% of inoculation. Under the optimized fermentation conditions, the highest chitinase activity of 5.5 U/mL was achieved,which is 4.2-fold of the initial chitinase porduction. The relative high enzyme activity was helpful for further study on the purification and characterization of chitinase from this strain.