• 作者： 蘇遠志; 劉文雄; 張麗雲
• 作者服務機構： 國立臺灣大學農業化學系
• 中文摘要： 本研究從果實中分離出一種不完全菌Pullularia pullulans能將葡萄糖或澱粉糖化液醱酵生產多量之葡萄糖酸。利用此菌株生產葡萄糖酸鈉之最適醱酵條件如下：培養基組成：(1)種菌培養基：葡萄糖或澱粉糖化液12%，氯化鈉0.2，磷酸一鉀0．125，硫酸鎂0 ．125Yo；pH 6．0“(2)生產培養基：葡萄糖或澱粉糖化液20Y,，硫酸銨0.05，磷酸一鉀0．1％，硫酸鎂0.05%；pH 7·8-8·Oo培養條件：使用5 E-jar fermentor裝入殺菌過之上述生產培養基，並接入20彫量之種菌培養液，於培養溫度26-280C，攪拌速率500rpm，通氣量1.5 vlv/min.之條件下進行通氣攪拌培養，在培養期問中以5NNaOH調節培養液之pH至7.8-.-8.0“於此條件下培養35小時後，葡萄糖酸鈉對葡萄糖之收率為97%。若對醱酵液添加0.1%活性碳，加以脫色、過濾後，瀘液以Amberlite IRC-120脫鈉、真空濃縮及真空乾燥等之處理後，即可獲得純度96.8%之葡萄糖酸內酯，其對醱酵液中葡萄糖酸之收率為85％。 Pullularia pullulans所分祕菌體外葡萄糖氧化?以分批式培養20小時或在連續式培養中任何定常狀態下均可獲得最高酵素活性。以各種不溶性擔體檢討固定粗葡萄糖氧化?之適當方法，初步得知以DEAE-Sephadex A-25之結果最佳。水溶性酵素及不溶性酵素之最適作用溫度各為250C及300C，而兩者之最適作用pH值則均為6．0。不溶性酵素之熱穩定性比水溶性酵素較佳。
• 英文摘要： Pullularia pullulans, one of the fungi imperfecti，was found to utilizeglucose (or starch hydrolyzate) for the production of gluconic acid bysubmerged fermentation. Further experiments revealed that a considerableamount of sodium gluconate was produced when this microorganism wasgrown on the following medium: (1) seed culture: glucose (or starchhydrolyzate as glucose)，12%; NH4C1，0.2%; KH2P04, 0.125%; MgS04·7H,0,0.125%. (2) main culture: glucose (or starch hydrolyzate)，20%; (NH4)2S04,0.05%; KHZP04> 0.1％：MgS04·7H20, 0.05%. During incubation at 26-280C,pH was adjusted to 6.0 (in seed culture) or 7.8-8.0 (in main culture) by theaddition of 5 N NaOH. The fermentation was agitated at 500 rpm withair input at 1.5 volume per volume of medium per minute. After 35 hr offermentation, 97% of the reducing sugar from the 20% glucose medium wasconverted to sodium gluconate. Glucono-delta-lactone was also obtainedfrom the fermentation liquor through an ion exchange treatment, evapora-tion, and dehydration under vacuo．The yield of glucono-delta-lactone was85%. The maximum activity of extracellular glucose oxidase of P. pullulanswas obtained by a batch process after 20 [hr of cultivation or by a con-tinuous process at steady-state of cultivation. The immobilization of the partial purified glucose oxidase by various water-insoluble carriers was carried out, and it was found that the enzyme was favorably immobilized by DEAE-Sephadex A-25. The optimal temperature of native and immo－ bilized glucose oxidase were found to be 250C and 30“C, respectively. The optimal pH of native and immobilized glucose oxidase was 6.0 in both cases. The heat stability of immobilized enzyme was more stable than that of the native one. It is well known that gluconic acid and its salts may be used in the pharma-ceutical, beverage, food and textile industries. Gluconic acid was produced fromglucose by microbial process using various molds‘’一‘“）or bacteria‘”）．At present,all gluconate are commercially produced by fermentation with Aspergillus niger 7）． Recently, interest in gluconic acid was stimulated by the increasing demandfor sodium gluconate and glucono-delta-lactone because of the sequestering abilityof the gluconate radical which remains active in alkaline solutions; in the dairyindustry to prevent milkstone; in breweries to prevent beerstone; as latent acidcatalyst for acid resins, particularly in textile printing. In order to promote theeconomical value of local starch, one of the fungi imperfecti，Pullularia pullulans,which could produce large amounts of gluconic acid from glucose or starchhydrolyzate has been isolated by authors. The suitable fermentation conditionsfor the direct production of sodium gluconate from local starch by this newlyisolated P. pullulans and the suitable method for the preparation of glucono-delta-lactone from sodium gluconate were investigated． Since the detection of glucose oxidase in extracts from Asp. niger, significantprogess has been made on methods for the purification of this enzyme from variousfungal sources' 12-11）and on the elucidation of the mode of action of the enzyme"',is，17）．On the other hand, in recent years there has been considerable interest instudy of the preparation and application of immobilized enzymes. Among these,glucose oxidase (EC 1．1.3.4) from Asp. niger which catalyzes oxidation of glucoseinto gluconic acid have widely attracted many investigators, and some immobilizedmethods have been undertaken' 11-2‘）．However, the production of gluconic acidthrough the enzymatic process by using immobilized glucose oxidase is still notdeveloped. The purpose of this series study is to develop an enzymatic process by usingimmobilized glucose oxidase of P. pullulans for the production of gluconic acid fromglucose. Then, an economic evaluation of the enzymatically-catalyzed synthesiswill be performed for comparison with the microbial fermentation. In this report,the microbial fermentation for the production of sodium gluconate and a prelimin-ary study on the preparation of immobilized glucose oxidase of P. pullulans will bepresented.
• 中文關鍵字： --
• 英文關鍵字： --