Abstract

Solid-State Fermentation (SSF) defined as a system in which the growth of microorganisms occurs on a moist solid substrate, shows tremendous potential in applications of microbial enzyme production as a low-cost, low-energy option. In this work, the production of lipase from Penicillium aurantiogriseum by using SSF was investigated. For this purpose, the sunflower pulp, an agro-industrial by-product, was utilized as a solid substrate in the SSF method. The optimization and characterization studies for lipase extract were performed by using the p-nitrophenyl palmitate (pNPP) (C16) as substrate. The lipase activity was found as 29.6 ± 0.11 U/mg protein at optimum conditions (50 mM of Tris-HCl buffer, pH 7.0, 40 °C). In thermal stability assay, the catalytic activities of lipase which are kept at 40, 50 and, 60 °C in a water bath for 1 h, were calculated as 100%, 60.48 ± 1.3%, 32.67 ± 0.2%, respectively. Also, the enzyme lost rapidly its activity within 15 min at 70 °C. The kinetic data, K_m and V_max, were determined as 0.17 mM and 2.9 µM/min, respectively. Also, 10 mM of Ba⁺² ion had a slight activating effect (15%) showed on lipase. Lipase kept about 50% of its activity at 4 °C at the end of the 30 days. The hydrolytic activities of lipase for commercial olive oil and sunflower oil were found as 3.52 ± 0.1 U/mg and 3.90 ± 0.12 U/mg, respectively. The SSF method had obvious potential for the sustainable and cost-effective production of lipase from P. aurantiogriseum. Also, these results confirmed that the sunflower pulp could be used as an alternative substrate to produce enzymes in SSF conditions.

摘要

固态发酵 (SSF) 定义为微生物在潮湿的固体基质上生长的系统，作为一种低成本、低能量的选择，在微生物酶生产的应用中显示出巨大的潜力。在这项工作中，研究了使用 SSF从青霉中生产脂肪酶。为此，向日葵果肉是一种农业工业副产品，在 SSF 方法中用作固体基质。脂肪酶提取物的优化和表征研究是通过使用对硝基苯基棕榈酸酯 ( pNPP) (C16) 作为底物。在最佳条件下（50 mM Tris-HCl 缓冲液，pH 7.0，40 °C），脂肪酶活性为 29.6 ± 0.11 U/mg 蛋白质。在热稳定性试验中，脂肪酶在 40、50 和 60°C 的水浴中保持 1 小时的催化活性分别计算为 100%、60.48±1.3%、32.67±0.2%。此外，该酶在 70°C 下 15 分钟内迅速失去活性。动力学数据 K _m和 V _max分别测定为 0.17 mM 和 2.9 µM/min。此外，10 mM Ba ⁺²离子对脂肪酶有轻微的活化作用（15%）。在 30 天结束时，脂肪酶在 4 °C 下保持其活性的约 50%。脂肪酶对商业橄榄油和葵花籽油的水解活性分别为 3.52 ± 0.1 U/mg 和 3.90 ± 0.12 U/mg。SSF 方法对于从P. aurantogriseum可持续且具有成本效益地生产脂肪酶具有明显的潜力。此外，这些结果证实，向日葵果肉可用作替代底物，在 SSF 条件下生产酶。