The objective of this study was to evaluate the effects of nitrogen and carbon source on cellulase activity of Aspergillus niger ITV 02. The results obtained showed that nitrogen had an influence on the increase in cellulase activity by A. niger ITV 02 during submerged fermentation. Optimal concentrations obtained from nitrogen sources, using a Box–Behnken design were 0.9 g/L urea, 2.4 g/L ammonium sulfate and 1.5 g/L yeast extract, obtaining endoglucanase and β-glucosidase specific activities of 24.63 U/mg and 72.66 U/mg, respectively, at 50 h of fermentation. Subsequently, the effect of three carbon sources was evaluated: carboxymethylcellulose, delignified sweet sorghum bagasse (DSSB) and sweet sorghum bagasse cellulose (SSBC). Maximum cellulase specific activity was obtained when using DSSB, increasing endoglucanase activity fivefold and β-glucosidase activity 1.25-fold (126.72 and 85 U/mg) respectively. SSBC hydrolysis using enzymatic extract produced 18 g/L reducing sugars, equivalent to a 25% residue conversion. These results showed that it is possible to obtain an extract with cellulase activity from A. niger ITV 02 to be used in SSBC hydrolysis using low-cost substrates such as DSSB, which would contribute to a reduction in second-generation ethanol process production costs and an increase in the availability of enzymes for this use.

中文翻译：

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利用Box–Behnken设计优化黑糖曲霉ITV 02提取甜高粱甘蔗渣在深层培养中的纤维素酶生产

这项研究的目的是评估氮和碳源对黑曲霉ITV 02纤维素酶活性的影响。结果表明，氮对黑曲霉纤维素酶活性的增加有影响。浸入式发酵过程中的ITV 02。使用Box–Behnken设计从氮源获得的最佳浓度为0.9 g / L尿素，2.4 g / L硫酸铵和1.5 g / L酵母提取物，获得的内切葡聚糖酶和β-葡萄糖苷酶比活分别为24.63 U / mg和72.66 U在发酵50 h时，每毫克分别为100 mg / mg。随后，评估了三种碳源的效果：羧甲基纤维素，脱木质素的甜高粱甘蔗渣（DSSB）和甜高粱甘蔗渣纤维素（SSBC）。当使用DSSB时，纤维素酶的最大活性最高，内切葡聚糖酶的活性提高了5倍，β-葡萄糖苷酶的活性分别提高了1.25倍（126.72和85 U / mg）。使用酶提取物的SSBC水解产生18 g / L还原糖，相当于25％的残留转化率。将使用低成本底物（例如DSSB）在SSBC水解中使用黑曲霉ITV 02，这将有助于降低第二代乙醇工艺的生产成本，并增加用于此用途的酶的利用率。