Abstract

Two biocatalysts with high lipolytic activity were obtained – freeze-dried supernatant and freeze-dried biomass of Yarrowia lipolytica KKP 379. The biocatalysts were compared with Candida antarctica lipase B in the synthesis of ethyl hydrocinnamate – a flavour compound with a floral-honey aroma. Ester synthesis was completed after 2 h when 3 grams of freeze-dried biomass was used. Using smaller amounts of biomass (1.2 and 0.6 g) also allowed to achieve high ester conversion and results were comparable with those obtained for CALB used as a catalyst. Freeze-dried supernatant showed a weaker lipase activity (22.17 U/g) compared to freeze-dried biomass (46.13 U/g), which resulted in a lower conversion of 3-phenylpropionic acid to its ethyl ester, and after 36 h a conversion peaked at around 70%, then began to decrease and finally the conversion reached 50%. Moreover, antimicrobial and antioxidant properties of the synthesised ester were evaluated. Ethyl hydrocinnamate showed no antibacterial activity and weak antioxidant activity towards DPPH radical. In contrast to bacteria, the obtained compound moderately inhibited the growth of tested yeast species, where inhibition zones ranged from 10 to 16 mm.

摘要

获得了两种具有高脂解活性的生物催化剂——解脂耶氏酵母KKP 379 的冻干上清液和冻干生物质。将生物催化剂与南极念珠菌进行比较脂肪酶 B 合成氢化肉桂酸乙酯——一种具有花蜜香味的风味化合物。当使用 3 克冻干生物质时，酯合成在 2 小时后完成。使用更少量的生物质（1.2 和 0.6 克）也可以实现高酯转化率，结果与用作催化剂的 CALB 获得的结果相当。与冷冻干燥的生物质 (46.13 U/g) 相比，冷冻干燥的上清液显示出较弱的脂肪酶活性 (22.17 U/g)，这导致 3-苯基丙酸向其乙酯的转化率较低，并且在 36 公顷后转化率达到峰值在 70% 左右，然后开始下降，最终转化率达到 50%。此外，还评估了合成酯的抗菌和抗氧化性能。氢化肉桂酸乙酯对DPPH自由基无抗菌活性和弱抗氧化活性。与细菌相比，所获得的化合物适度抑制了测试酵母物种的生长，其中抑制区范围为 10 至 16 毫米。