具分解幾丁質能力菌株之篩選

本研究目的為自土壤中篩選具有分解幾丁質能力之菌株。從雲林縣濁水溪河畔之土壤，篩選出具此能力之菌株，經鑑定後，命名為Aeromonas caviae DYU-BT4。此菌株在LB(Luria-Bertani)培養基中培養，於第12 h達生長平衡期，發酵液中還原醣量在培養24 h時為0.88g/L，幾丁質水解產物以N-乙醯葡萄糖胺為主，粗酵素液於pH 6~7時，具有較佳反應活性，酵素液與基質之較佳反應溫度為50℃。將此菌株培養於蝦殼粉、烏賊軟骨、幾丁質粉末及膠態幾丁質中，分析其水解產物，N-乙醯葡萄糖胺含量以膠態幾丁質為培養基時為最高。若以1%、2%及4%幾丁質粉末為碳源，批次發酵培養此菌株，當菌體生長至平衡期時，幾丁質酶活性與還原醣含量皆不再有明顯變化。生質量、還原醣及幾丁質酶活性皆以含2%幾丁質之CB (chitin broth)培養基為最高，至於N-乙醯葡萄糖胺之產量則以含4%幾丁質之CB培養時為最高。

關鍵字

幾丁質； Aeromonas caviae ；幾丁質酶；篩菌

並列摘要

The purpose of this study was to screen indigenous microorganisms from soil to degrade chitin and to produce hydrolysates of chitin. A microbe, designated as DYU-BT4, was isolated from the soil of ZwouShau Creek in the Yun-lin County. The microbe had been identified and coded as Aeromonas caviae DYUBT4. The microbe was cultured in the Luria-Bertani medium and reached the stationary phase in about 12 h. The concentration of reducing sugars in the medium was 0.88 g/L at 24 h. The major substance in the hydrolysate of chitin was N-acetylglucosamine. The optimal reaction conditions of the crude enzyme in the supernatant were met with the pH between 6 and 7, and the temperature 50℃. The microbe was also cultivated in media containing various carbon-sources, such as shrimp shell powder, squid pen, chitin powder and colloidal chitin. Production of N-acetylglucosamine was maximized in the colloidal chitin medium. When the microbe was cultivated in a batch bioreactor with 1%, 2% and 4% chitin powder as the carbon source, both the chitinase activity and the reducing sugar concentration did not significantly vary after the stationary phase. All of the biomass, reducing sugars and chitin activity were maximum in the 2% chitin broth, and the highest production of N-acetylglucosamine occurred in the 4% chitin broth.

並列關鍵字

Chitin ； Aeromonas caviae ； Chitinase ； Screening of microbes

國際替代計量

具分解幾丁質能力菌株之篩選

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