Ademakinwa Adedeji Nelson, Ayinla Zainab Adenike, Agunbiade Mayowa Oladele
Biochemistry Program, Department of Physical and Chemical Sciences, Elizade University, Nigeria.
Department of Biology, University of Waterloo, Canada.
Int J Biol Macromol. 2025 Apr;304(Pt 1):140781. doi: 10.1016/j.ijbiomac.2025.140781. Epub 2025 Feb 8.
The aim of this study was to purify, characterize, and evaluate the potential of the immobilized extracellular lipase from Aureobasidium pullulans NAC8 (ApL) for the biodegradation of oil-contaminated wastewater. ApL was purified using aqueous two-phase partitioning (ATPS) and its biochemical properties determined. The enzyme was then covalently immobilized and characterized through Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The performance of immobilized ApL in oil-contaminated wastewater was tested for its ability to remove chemical oxygen demand (COD), hydrolyze lipids, and produce free fatty acids. The purification fold and yield of ApL were 3.5 and 66 %, respectively. The purified enzyme had a subunit molecular weight of 30 kDa, with an optimum pH of 6.5 and an optimum temperature of 50 °C. The enzyme's catalytic efficiency for pNPP and pNPB was 1.53 × 10 and 2.3 × 10 in aqueous media, and 1.74 × 10 and 2.7 × 10 in organic solvent. Thermodynamic analysis revealed values for ∆H* (16.4 kJ/mol), ∆S* (-214 J/mol/K), and ∆G* (70.1-88.4 kJ/mol), indicating stability against thermal denaturation between 40 and 70 °C. The immobilized enzyme retained 70 % of its activity after ten catalytic cycles. In oil-contaminated wastewater, it achieved 83 % COD removal, 7.4 % lipid hydrolysis, and 15 % free fatty acid production after five cycles. The biochemical characteristics of the purified and immobilized ApL suggest that it has significant potential for industrial applications, particularly in the biodegradation of oil-contaminated wastewater. Its stability and high catalytic efficiency make it a promising candidate for long-term environmental and industrial use.
本研究的目的是纯化、表征并评估来自出芽短梗霉NAC8（ApL）的固定化胞外脂肪酶对含油废水的生物降解潜力。使用双水相萃取（ATPS）纯化ApL并测定其生化特性。然后通过傅里叶变换红外（FTIR）光谱和扫描电子显微镜（SEM）对该酶进行共价固定和表征。测试了固定化ApL在含油废水中去除化学需氧量（COD）、水解脂质和产生游离脂肪酸的能力。ApL的纯化倍数和产率分别为3.5和66%。纯化后的酶亚基分子量为30 kDa，最适pH为6.5，最适温度为50℃。该酶在水介质中对对硝基苯磷酸酯（pNPP）和对硝基苯丁酸酯（pNPB）的催化效率分别为1.53×10和2.3×10，在有机溶剂中分别为1.74×10和2.7×10。热力学分析显示ΔH*（16.4 kJ/mol）、ΔS*（-214 J/mol/K）和ΔG*（70.1 - 88.4 kJ/mol）的值，表明在40至70℃之间对热变性具有稳定性。固定化酶在十个催化循环后保留了70%的活性。在含油废水中，五个循环后它实现了83%的COD去除、7.4%的脂质水解和15%的游离脂肪酸产生。纯化和固定化ApL的生化特性表明它在工业应用中具有巨大潜力，特别是在含油废水的生物降解方面。其稳定性和高催化效率使其成为长期环境和工业应用的有前途的候选者。
