利用固定化Leuconostoc sp. M-1進行蘋果酸乳酸醱酵

Abstract

由六株乳酸菌中選出Leu. sp M-1固定於calcium alginate膠體上，進行蘋果酸乳酸醱酵。Leu. sp M-1培養在蕃茄汁培養基，離心收集細胞，加入10 ml無菌水，做成細菌懸浮液（約108 cells/ml）添加到20 ml 3％ Na-alginate混合後逐滴滴入0.1 MCaCl2溶液中形成珠狀膠體，取300粒固定化膠體在28℃蕃茄汁培養基活化24小時之後，加入30 ml實驗用培養基，內含3 ml/l醋酸，1.1g/l CaCl2，8 g/l蘋果酸，0.68 g/l磷酸二氫鉀，PH4.4在28℃旋轉式振盪器做分批式醱酵，醱酵後蘋果酸於第十二小時轉變?乳酸，總酸度由0.65 ml/ml降至0.15ml/ml，培養基PH值由4.40升至5.50。Mn2+，Mg2+及K+的添加可以促進蘋果酸乳酸醱酵，每日換新鮮培養基，可維持醱酵達12?15天，活性才消失，若經再活化處理，又可繼續使用到膠體破裂?止。以連續醱酵的方式，反應前8天可將培養液中的蘋果酸完全分解，第9天後活性下降。在葡萄汁及葡萄酒中亦可用固定化乳酸菌進行蘋果酸乳酸醱酵。

Leuconostoc sp. M-1 was selected from six lactic acid bacteria and immobilized on calcium alginate for malolactic fermentation. Leuconostoc sp. M-1 cells grown in Tomato juice broth were collected by centrifugation and resuspened in 10 ml of sterile water (about 108 cells/ml) then mixed with 20 ml 3% sodium alginate. The suspension was added dropwise to 0.1M CaCl2 solution to form gel beads. After activation by incubation at 28℃ for 24 hours in Tomato juice broth, three hundred beads of immobilized cells were inoculated into 30ml fermentation medium containing 3 ml/l acetic acid, 1.1 g/l CaCl2, 8 g/l L-malic acid, 0.68 g/l KH2PO4, pH 4.40. After fermentation at 28℃ for 12 hours by shaking, L-malic acid were converted to L-lactic acid completely, the total acidity decreased from 0.65 ml/ml to 0. 15 ml/ml and medium pH increased from 4.40 to 5.50. The malolactic fermentation by immobilized cells could be stinulated by the addition of Mn2+, Mg2+, K+. The medium was renewed daily for batch culture, fermentation could perform for 12-15 day then activities desappeared. Immobilized cells could be reused by reactivation until they broke. In continuous fermentation, L-malic acid was degraded completely during first 8 days, then the activity decreased. The fermentation by immobilized cells could also perform in grape juice and in wine.