以固態培養Aspergillus屬真菌生產酸性蛋白酶之研究

Production of Acid Protease from the Fungal Aspergillus sp. by Solid-state Fermentation

酸性蛋白酶屬於水解酶的一種，廣泛運用在食品、醫藥、皮革工業與飼料添加劑上，由於酸性蛋白酶的耐酸特性可適應腸胃道的酸性條件，能有助於畜禽對蛋白質的吸收。藉由Aspergillus sp.屬真菌生產酸性蛋白酶，可進一步做為飼料添加劑的使用。在本研究中，我們以麩皮做為固態發酵主要基質生產酸性蛋白酶，溫度與含水量為固態發酵之重要參數，生產酸性蛋白酶之最佳發酵溫度及含水量分別為30oC及120%，同時運用變溫策略可有效提高酸性蛋白酶活性17%，使活性達42.04U/g。可藉由飽和硫酸銨濃度60-100%沉澱法將經由Aspergillus sp.屬真菌生產固態發酵物水萃物之酸性蛋白酶沉澱析出，發現可回收90%酸性蛋白酶。

Acid protease is a kind of hydrolase with wide applications in food processing、medical purpose、leather processing and feeds. Acid protease having stability in acidic and neutral conditions can adapt digestion systems of animals, which can increase the digestion and absorption rate of feed nutrients. The fungal strain Aspergillus sp. is capable of producing an acid protease that can be used as a feed additive.In the study, we used wheat bran as the major solid substrate to produce acid protease. The effect of cultivation parameters including temperature and moisture were also the important fermentation parameters for the solid state fermentation. The optimal temperature and moisture of solid fermentation for the production of acid protease were 30 oC and 120%, respectively. The strategy of change temperature during the period of fermentation effectively increases 17% in the activity of acid protease to 42.04U/g. The crude acid protease can be recovery 90% from crude extract liquid by ammonium sulfate fractionation between ammonium sulfate percent saturation concentration from 60% to 100% .