木聚糖酶高产菌株EIM-30的鉴定及其产酶条件的优化

Identification of xylanase-producing fungi EIM-30 and its optimization of submerged fermentation conditions

通过对木聚糖酶高产菌株EIM-30基于形态学和18SrDNA序列的系统发育进化分析，鉴定为里氏木霉Trichoder撇reesei。在单因子实验确定EIM-30产木聚糖酶的最适碳源和氮源的基础上，通过Plackett—Burman实验对影响其产酶的相关因素进行评估并筛选出3个显著效应因子，然后应用最陡爬坡实验和响应面分析确定最适产酶培养基配方为：酵母浸膏1．50％，蛋白胨1．00％，NaC10．50％，PPG-20000．10％，MgS041．20％，CaC20．18％，（NH4）2S040．45％，甘油4．18％，乳糖3．05％，K2唧041．59％。优化后TrichodermareeseiEIM-30的液体发酵产木聚糖酶的活力可达9．857×105V／mL，较优化前提高1．98倍。

A high xylanase-producing strain EIM-30 was identified as Trichoderma reesei based on its molecular phylogenetic analysis of 18S rDNA sequences. The optimum carbon and nitrogen sources for EIM-30 producing xylanase were obtained by the single factor experiments. Then, some factors under submerged fermentation conditions were evaluated and three factors demonstrated prominent effects on producing xylanase were respectively selected by Plackett- Burman design. The suitable medium obtained by steepest ascent design and response surface experiment were as follows： yeast extract 1.50%, peptone 1.00%, NaC1 0.50%, PPG-2000 0.10%, MgSO41.20%, CaCl2 0.18%, （NH4）2 SO4 0.45 %, glycerin 4.18 %, lactose 3.05 % and K2HPO4 1.59 %. After optimization, the xylanase activity of Trichoderma reesei EIM-30 reached as high as 9. 857 × 105 U/mL, which increased 1.98 times than before.