里氏木霉固体发酵产孢条件的研究(英文)

Study on Sporulation Conditions of Trichoderma reesei by Solid Fermentation

[目的]研究里氏木霉的固体发酵产孢条件。[方法]以产生孢子的数量作为响应值,应用单因素试验、Plackett-Burmam试验、最陡爬坡试验、Box-Behnken试验和响应面分析法对里氏木霉固体发酵产生孢子的条件进行优化。[结果]通过单因素试验确定里氏木霉最适合碳源为稻草粉和麦麸,其含量比值为3∶2,最合适量为15g;最合适无机氮源为(NH4)2SO4,最合适量为2g;利用Plackett-Burmam确定了含水量、起始pH和培养温度是影响里氏木霉孢子产量的显著性因素;通过最陡爬坡试验逼近了最大孢子产量区域,并利用Box-Behnken设计及响应面分析法确定最大产胞量的最佳发酵条件为:稻草杆粉6g、麦麸9g、(NH4)2SO42g、含水量65%、培养温度29℃、发酵周期72h、起始pH5.5,此时孢子数量为2×1010个/g,是优化前产量的1.4倍。[结论]该试验利用低廉的稻草杆粉和麦麸为碳源优化了里氏木霉固体发酵产生孢子的生产条件,有助于降低里氏木霉的生产成本,提高里氏木霉的孢子产量,具有一定的社会和经济意义。

[Objective] This study aimed to investigate the sporulation conditions of Tri- choderma reesei by solid fermentation. [Method] With sporulation yield as the response value, single-factor test, Plackett-Burmam design, steepest ascent test, BoxBehnken design and response surface analysis were employed to optimize the con- ditions for sporulation of Trichoderma reesei by solid fermentation. [Result] Based on single-factor test, the most appropriate carbon source for Trichoderma reesei was straw stalk powder and wheat bran with the ratio of 3：2 and optimal amount of 15 g/L; the most appropriate inorganic nitrogen was （NH4）2O4 with the optimal amount of 3 g/L. According to Plackett-Burmam design, moisture content, initial pH and incubation temperature were identified as significant factors affecting the sporulation yield of Trichoderma reeseL The maximum sporulation yield area was approached by steepest ascent test. Based on Box-Behnken design and response surface analysis, the optimal fermentation conditions for the maximum sporulation yield were determined as： straw stalk powder of 6 g/L, wheat bran of 9 g/L, （NH4）2SO4 of 3 g/L, moisture content of 65%, incubation temperature of 29 ℃, fermentation period of 72 h and initial pH of 5.5, under these conditions, the sporulation yield reached 2×10^10 spores/g, which was improved by 1.4 times compared with that before optimization. [Conclusion] In this study, the conditions for sporulation of Trichoderma reesei by solid fermentation were optimized with low-cost straw stalk powder and wheat bran as carbon sources, which was conducive to reducing the production cost of Trichoderma reesei and increasing the sporulation yield, showing certain social and economic significance.