Loo Joo Ling, Khoramnia Anahita, Lai Oi Ming, Long Kamariah, Ghazali Hasanah Mohd
Department of Food Science, Faculty of Food Science and Technology, University Putra Malaysia, 43400 Serdang, Malaysia.
Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400 Serdang, Malaysia.
Molecules. 2014 Jun 23;19(6):8556-70. doi: 10.3390/molecules19068556.
Mycelium-bound lipase (MBL), from a locally isolated Geotrichum candidum strain, was produced and characterized as a natural immobilized lipase. A time course study of its lipolytic activity in 1 L liquid broth revealed the maximum MBL activity at 4 h for mycelium cells harvested after 54 h. The yield and specific activity of MBL were 3.87 g/L dry weight and 508.33 U/g protein, respectively, while less than 0.2 U/mL lipase activity was detected in the culture supernatant. Prolonged incubation caused release of the bound lipase into the growth medium. The growth pattern of G. candidum, and production and properties of MBL were not affected by the scale. The stability of mycelia harboring lipase (MBL), harvested and lyophilized after 54 h, studied at 4 °C depicted a loss of 4.3% and 30% in MBL activity after 1 and 8 months, while the activity of free lipase was totally lost after 14 days of storage. The MBL from G. candidum displayed high substrate selectivity for unsaturated fatty acids containing a cis-9 double bond, even in crude form. This unique specificity of MBL could be a direct, simple and inexpensive way in the fats and oil industry for the selective hydrolysis or transesterification of cis-9 fatty acid residues in natural triacylglycerols.
从本地分离的白地霉菌株中制备了菌丝体结合脂肪酶（MBL），并将其表征为一种天然固定化脂肪酶。对其在1 L液体培养基中的脂解活性进行的时间进程研究表明，对于在54 h后收获的菌丝体细胞，MBL活性在4 h时达到最高。MBL的产量和比活性分别为3.87 g/L干重和508.33 U/g蛋白质，而在培养上清液中检测到的脂肪酶活性低于0.2 U/mL。长时间孵育会导致结合的脂肪酶释放到生长培养基中。白地霉的生长模式以及MBL的产生和性质不受规模的影响。对54 h后收获并冻干的含有脂肪酶的菌丝体（MBL）在4℃下进行稳定性研究，结果表明，在1个月和8个月后，MBL活性分别损失4.3%和30%，而游离脂肪酶的活性在储存14天后完全丧失。即使是粗制形式，来自白地霉的MBL对含有顺式-9双键的不饱和脂肪酸也表现出高底物选择性。MBL的这种独特特异性可能是油脂工业中对天然三酰甘油中顺式-9脂肪酸残基进行选择性水解或酯交换的一种直接、简单且廉价的方法。
