- 期刊
Bacillus smithii固態發酵痲瘋樹餅粕最適化生產木聚糖酶
Solid State Production of Xylanase using Deoiled Jatropha curcas Seed Cake by Bacillus smithii
摘要
痲瘋樹餅粕 (Jatropha curcas seed cake) 是生質柴油生產過程中的主要副產物。餅粕具有高的營養成分包括蛋白質、礦物質與胺基酸等適合當作動物飼料、有機肥料與微生物生長的營養基質。由於餅粕組成分中含毒性成份佛波酯 (phorbol esters, PEs)，使得其利用性受到限制。本研究利用痲瘋樹脫油餅粕接種Bacillus smithii G16進行固態發酵，除能有效的分解佛波酯外，同時進行最適化木聚糖酶的生產。不同菌株 (Bacillus smithii G16、B. sonorensis D12與B. subtilis H8) 木聚糖酶生產能力的篩選結果顯示，B. smithii G16能有效的利用餅粕進行生長及分解餅粕中的佛波酯並有最高木聚糖酶活性。進一步測試包括培養時間 (1-9天)、初始水分含量(40、50、60% w/w)、初始接種菌量 (10^6、10^7、10^8 CFU/g)、培養溫度 (25、35、50℃ )、碳源 (1%葡萄糖、1%甘露糖、1%澱粉w/w) 與氮源 (0.5%硝酸鈉、0.5%氯化銨、0.5%蛋白腖w/w) 對木聚糖酶生產活性的影響。實驗結果顯示，利用B. smithii G16生產木聚糖酶的最佳培養條件為: 50%初始水分含量、接種108 CFU/g的菌量、培養在35℃ 溫度下、添加1%葡萄糖與0.5%蛋白腖培養2天後有最佳酵素活性26.55 ± 0.37 U/g。
並列摘要
Oil extraction of Jatropha curcas seed had created the large amount of cake by-product. Deoiled J. curcas seed cake is rich of protein and other different nutrients like minerals, and amino acids were suitable to use as the nutrients for microbial growth. Deoiled J. curcas seed cake was assessed as substrate for the production of extracellular xylanase by Bacillus smithii G16 in solid state fermentation. The seed cake was efficiently utilized by B. smithii G16 for its growth and phorbol ester degradation during which it produced extracellular xylanase. Initial screening process identified the best xylanase production strains, and then different parameters such as incubation time (day 1-9), initial moisture content (40%, 50%, 60%), incubation temperature (25℃, 35℃, 50℃), inoculum level (10^6, 10^7, 10^8 CFU/g), carbon sources (1% glucose, 1% maltose, 1% starch), and nitrogen sources (0.5% NaNO_3, 0.5% NH_4NO_3, 0.5% peptone) of the medium were optimized. The optimum conditions for the xylanase production by B. smithii G16 obtained from this experiment were 50% substrate moisture, 35℃ incubation temperature, a growth period of 48 h, inoculated with 10^8 CFU per 1 g cake, supplemented with 1% glucose and 0.5% peptone, 26.55 ± 0.37 U xylanase activity per gram of Jatropha seed cake was obtained. Solid-state fermentation of deoiled J. curcas cake appears a potentially viable approach for its effective utilization.