Abstract:

In recent years, the application of whole-cell biocatalyst in biodiesel production has attracted great attention. Whole-cell catalyst avoids the cumbersome enzyme purification process and saves the preparation cost of the catalyst. Moreover, whole-cell biocatalyst has a long service life. In this study, a strain of Rhizopus oryzae with high lipase production was immobilized and applied. Different immobilization materials were selected and the suitable immobilization conditions were explored. The immobilized Rhizopus oryzae as the whole-cell catalyst was used to catalyze the preparation of biodiesel from Comus wilsoniana fruit oil. The effect of esterification conditions on the yield of biodiesel was discussed. The results showed that the immobilization rate and activity of the immobilized cells were the highest with the loofah sponge as the immobilization material, olive oil as carbon source,and peptone and NaNO₃ as compound nitrogen source. In the reaction system of 10% water content and 12% catalyst dosage, the molar ratio of total alcohol to oil was 4∶1, methanol was added 1∶1 at 0h, 10h, 24h, 40h, respectively, and the yield of methyl ester was more than 94%. After the immobilized whole-cells were reused for 6 times, the transesterification acticity of immobilized cells remained above 80%.

Key words: whole-cell catalyst, Rhizopus oryzae, loofah sponge, biodiesel, Comus wilsoniana fruit oil

摘要：

近年来，全细胞生物催化剂应用于生物柴油生产的研究引起了人们的极大关注，全细胞催化剂的制备过程可省去烦琐的酶纯化过程和降低催化剂的制备成本，且全细胞催化剂使用寿命较长。本研究对一株高产脂肪酶的米根霉进行了固定化研究，并将其应用于生物柴油的制备。首先筛选不同的生物基固定化材料，探索其适宜的固定化条件，以获得的固定化米根霉作为全细胞催化剂催化光皮树油制备生物柴油，探讨了转酯化条件对生物柴油得率的影响。研究结果表明，丝瓜络作为固定化材料的固载率最高，以橄榄油作为碳源，多聚蛋白胨和NaNO₃作为复合氮源，获得的固定化细胞的固载率及脂肪酶活性最强。以丝瓜络固定化米根霉催化光皮树油，在含水量为10%、催化剂用量为12%的反应体系中，总醇油摩尔比为4∶1，甲醇分别在0h、10h、24h、40h以1∶1添加，甲酯得率可达94%以上。固定化全细胞重复使用6次后，转酯化效果依然保持在80%以上。

关键词: 全细胞催化剂, 米根霉, 丝瓜络, 生物柴油, 光皮树油