SIMULTANEOUS PRODUCTION OF BIOSURFACTANTS AND LIPASES FROM Aspergillus niger AND OPTIMIZATION BY RESPONSE SURFACE METHODOLOGY AND DESIRABILITY FUNCTIONS

Abstract Microbial conversion for the synthesis of high added-value compounds, such as biosurfactants and lipases, is one of the most promising fields within the biotechnology industry, given its current development. In this study the simultaneous production of biosurfactants and lipases by Aspergillus niger in a submerged bioprocess was analyzed. Full Factorial Design (23) was conducted to assess the influence of the malt extract (g·L-1; 25, 50, 75) and soybean oil concentrations (% v/v; 0.0, 1.25, 2.5) and agitation rates (rpm; 0.0, 100, 200) on biosurfactant and lipase production. Higher levels of the factors favored microbial growth, while their lower levels favored the production of biosurfactants and lipases. The variables were optimized through the response surface methodology and desirability functions, obtaining simultaneous maximized values of 0.48 g·L-1 (biomass); 42.03% (EAw/o);2.17 UE (EAw/o) and 3.28 U (LA). This indicates the possibility of combined biosurfactant and lipase production.

摘要：微生物转化用于合成高附加值化合物（如生物表面活性剂（biosurfactants）与脂肪酶（lipases）），鉴于当前的发展态势，是生物技术产业中最具前景的领域之一。本研究针对黑曲霉（Aspergillus niger）在深层发酵工艺（submerged bioprocess）中同步生产生物表面活性剂与脂肪酶的过程展开分析。本研究采用全因子设计（Full Factorial Design，2³），考察麦芽提取物（质量浓度单位：g·L⁻¹，取值为25、50、75）、大豆油浓度（体积分数单位：% v/v，取值为0.0、1.25、2.5）以及搅拌速率（转速单位：rpm，取值为0.0、100、200）对生物表面活性剂与脂肪酶生产的影响。研究发现，各因素的高水平有利于微生物生长，而低水平则更利于生物表面活性剂与脂肪酶的合成。本研究通过响应面法（response surface methodology）与合意函数（desirability functions）对变量进行优化，得到同步最大化的指标值：生物量0.48 g·L⁻¹、乳化活性（EAw/o）42.03%、2.17 UE（EAw/o）以及3.28 U（LA）。这证实了同步生产生物表面活性剂与脂肪酶的可行性。