• 作者： 陳文彬; 陳建元; 蘇佳玲
• 作者服務機構： 國立中興大學食品科學研究所
• 中文摘要： 以 NTG (N-methyl-N’-nitro-nitrosoguanidine)化學變異誘導劑改良 Azotobactervinelandii NCIB-9068 並探討其最適之培養條件以生產細菌褐藻膠。經篩選出 C-14 變異株，其培養液之粘度較之野生株可提高約 40 倍。以 Burk 氏無氮培養基為基本培養基探討其成分之最適濃度，結果如下：蔗糖 20 克，磷酸一鉀0.3克，磷酸二鉀 1.2 克，硫酸鈣 0.15 克，硫酸亞鐵 15 毫克，鉬酸鈉 0.75 毫克，硫酸鎂 0.2 克，醋酸鈉2克，蒸餾水1升，pH6.5。其中以醋酸鈉對於提高膠濃度之效果非常顯著。在所探討之不同碳源中，以蔗糖之效果最佳，葡萄糖、山梨糖醇（sorbitol）、甘露糖醇（mannitol）次之。添加各種有機氮和無機氮之效果均不顯著，因此培養基不需添加任何氮源，可以降低生產成本。以上述之培養基於 28°C培養 C-14變異株 84 小時後，培養液之粘度高達 12,900cps，膠濃度為 5.54g/。與野生株比較，粘度約提高 100 倍，膠濃度增加為3倍。
• 英文摘要： In order to produce large amount ofbacterial alginate, Azotobacter vinelandiiNCIB-9068 was improved by mutation withNTG (N-methyl-N'-nitro-nitrosoguanidine)and the optimum cultivation conditions wereinvestigated. After mutation C-14 mutant wasselected for further study. The viscosity ofbroth could approximately increase 100-foldwhen compared with wild type. The Burk's nitrogen-free medium wasused as basal medium to study the optimumconcentration of each component. The resultwas as follows: sucrose, 20g; , 0.3g;,1.2g; , 0.15g; , 15mg; , 0.75mg;0.2g; , 2g; distilledwater, 1; pH, 6.5. Of the various compon-ents, sodium acetate had a significant effecton enhancing gum production. As a carbonsource, sucrose produced the best result. Thenext was glucose, sorbitol or mannitol.Addition of various organic or inorganicnitrogen sources had no significant effect ongum production. Thus, addition of nitrogensource was not required and the productioncost could be reduced. After cultivating C-14mutant in the optimum medium mentionedabove at 28°C for 84 hours the viscosity ofbroth was as high as 129,000 cps and the gumconcentration reached 5.54g/. When comp-ared with the wild type, the viscosity increased100-fold and 3-fold for gum concentration.
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