Baloch Khurshid Ahmed, Upaichit Apichat, Cheirsilp Benjamas, Fibriana Fidia
Molecular Biotechnology Laboratory, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, 90112, Songkhla, Thailand.
Biotechnology for Bioresource Utilization Laboratory, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, 90112, Songkhla, Thailand.
Curr Microbiol. 2021 May;78(5):1914-1925. doi: 10.1007/s00284-021-02448-2. Epub 2021 Apr 9.
Extracellular and cell-bound lipase-producing yeasts were isolated from the palm oil mill wastes and investigated for their potential uses as biocatalysts in biodiesel production. Twenty-six yeast strains were qualitatively screened as lipase producers. From those yeast strains, only six were selected and screened further for quantitative lipase production.The phylogenetic affiliations of the yeast strains were confirmed by investigating the D1/D2 domains of 26S rDNA and ITS1-5.8S-ITS2 molecular regions of the six yeast strains selected as potent lipase producers. The three yeast strains A4C, 18B, and 10F showed a close association with Magnusiomyces capitatus. Two yeast strains (17B and AgB) had a close relationship with Saprochaete clavata, whereas the strain AW2 was identified as Magnusiomyces spicifer. Three main catalytic activities of the yeast lipases were evaluated and Magnusiomyces capitatus A4C, among the selected lipase-producing yeasts, had the highest extracellular lipolytic enzyme activity (969 U/L) with the cell-bound lipolytic enzyme activity of 11.3 U/gdm. The maximum cell-bound lipolytic activity (12.4 U/gdm) was observed in the cell-bound lipase fraction produced by Magnusiomyces spicifer AW2 with an extracellular lipolytic enzyme activity of 886 U/L. Based on the specific hydrolytic enzymatic activities, the cell-bound lipases (CBLs) from the three yeast strains M. capitatus A4C, M. spicifer AW2, and Saprochaete clavata 17B were further investigated for biodiesel production. Among them, the CBL from M. spicifer AW2 synthesized the most FAME (fatty acid methyl esters) at 81.2% within 12 h indicating that it has potential for application in enzymatic biodiesel production.
从棕榈油厂废料中分离出胞外和细胞结合型产脂肪酶酵母，并研究其作为生物柴油生产中生物催化剂的潜在用途。对26株酵母菌株进行了产脂肪酶定性筛选。从这些酵母菌株中，仅选出6株进一步进行脂肪酶产量的定量筛选。通过研究6株被选为高效产脂肪酶酵母的26S rDNA的D1/D2结构域以及ITS1-5.8S-ITS2分子区域，确定了酵母菌株的系统发育关系。三株酵母菌株A4C、18B和10F与头状大孢酵母密切相关。两株酵母菌株（17B和AgB）与棒形腐殖酵母关系密切，而菌株AW2被鉴定为尖孢大孢酵母。评估了酵母脂肪酶的三种主要催化活性，在所筛选的产脂肪酶酵母中，头状大孢酵母A4C的胞外脂肪分解酶活性最高（969 U/L），细胞结合型脂肪分解酶活性为11.3 U/gdm。尖孢大孢酵母AW2产生的细胞结合型脂肪酶部分的细胞结合型脂肪分解活性最高（12.4 U/gdm），胞外脂肪分解酶活性为886 U/L。基于比水解酶活性，对三株酵母菌株头状大孢酵母A4C、尖孢大孢酵母AW2和棒形腐殖酵母17B的细胞结合型脂肪酶（CBL）在生物柴油生产中的应用进行了进一步研究。其中，尖孢大孢酵母AW2的CBL在12小时内合成的脂肪酸甲酯（FAME）最多，为81.2%，表明其在酶法生物柴油生产中具有应用潜力。
