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|標題:||Xylanase and xylooligosaccharides production by Aspergillus carneus M34 in solid state fermentation using low cost substrate
|關鍵字:||solid state ferments;固態發酵;xylanase;experiment design;xylooligosaccharides;immobilized enzyme.;聚木糖酶;實驗設計;固定化酵素;木寡糖||出版社:||食品科學系||摘要:||
The aim of this study was to develop a cost-down solid-state fermentation process for xylanase production from Aspergillus carneus M34. In addition, effects of various environmental conditions on the degradative activities of agricultural waste to produce xylooligosaccharides by the immobilized xylanase were evaluated as well.
In order to increase the xylanase activity of A. carneus M34, several strategies such as low cost agricultural wastes as the carbon sources and increasing inoculum size were used. For optimization of the medium composition, experimental designs including Plackett-Burman and response surface methodology (RSM) were practiced.
The results showed that when agricultural waster of coba husk and corn steep liquor was used in the ratio of 4.5:0.5, a 1.2 fold of increase in xylanase activity was observed. The incubation time for the xylanase production can be reduced from 12 days to 6 days by increasing the inoculum size at 2 × 107 spores/ml. The optimal medium compositions were as follows by using experimental designs including P lackett-Burman and RSM: carbon source, coba husk and corn steep liquor (4.5:0.5); NH4NO3, 3.24%; CaCl2, 0.1336%; MnSO4·7H2O, 0.001239%. Xylanase activity of 1721 U/g substrate can be produced by A. carneus M34 in 6 day by using this medium composition. We found that chitosan was the most suitable material to immobilized xylanase in this study, which with increase thermo-stability of the enzyme. For enzyme degradation of agricultural wastes including tea leaves, coba husk, bamboo, rice husk, soybean dregs, root of bamboo, bagasse, wheat bran and rice bran treated with alkaline and xylanase, 17.75 g reducing sugar /100g substrate was obtained from bagasse, which was the most suitable agricultural waste for this treatment.
本研究主要利用本實驗室所篩選出之Aspergillus carneus M34菌株，以固態發酵方式，開發廉價型聚木糖酶。此外，利用不同固定化方式固定化之聚木糖酶並利用不同農業廢棄物探討生產木寡糖之降解狀況。
實驗結果顯示出當農業廢棄物（茭白筍殼）與廉價營養源（corn steep liquor）在4.5:0.5之比例時最佳，可使聚木糖酶活性增加約20％。而接種量在2 × 107 spores/ml時，可將發酵時間由12天縮短至6天。在經由Plackett-Burman 實驗設計、陡升實驗及反應曲面法等實驗設計法檢討後，最適化培養基組成為茭白筍殼及corn steep liquor在4.5:0.5之比例，鹽離子濃度為NH4NO3, 3.24%; CaCl2, 0.1336%; MnSO4·7H2O, 0.001239%.時最佳，以此培養基組成發酵6天，聚木糖酶活性可達1721 U/g。此外，在研究中發現，該生產之廉價酵素，以幾丁聚醣吸附的固定化方式表現最佳，可增加酵素之熱穩定性。
而利用本研究生產之聚木糖酶在降解不同鹼處理之農業廢棄物中，包含茶渣、茭白筍殼、竹枝、稻殼、豆渣、筍根、甘蔗渣、麥麩及米糠，其中以甘蔗渣為最適合生產木寡糖之基質，產率為17.75 g 還原糖 /100g substrate。
|Appears in Collections:||食品暨應用生物科技學系|
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