| 摘要: | 先前本實驗室已篩出 B0014、B0059、B0096、B0137 等乳酸菌具有調降血壓的功能，因此本論文繼續以這四株乳酸菌進行最佳生產 GABA 之研究。以不同濃度培養基(4.5%與 8%豆漿粉)乳酸菌 B0096 發酵生產 GABA 之研究，結果顯示 B0096 發酵 4.5%豆漿粉培養基可得較高含量之 GABA。接續以乳酸菌 B0096 進行 GABA 生產條件探討，結果顯示 B0096 發酵 4.5%的豆漿粉培養 48 小時為生產 GABA 最佳的條件。再與 4.5%豆漿粉之基底培養基，添加 3%不同碳源(葡 萄糖、黑糖、蔗糖)作為培養基，接種 B0096 培養 48 小時，顯示添 加 3%葡萄糖為生產 GABA 最佳碳源。將含有 4.5%豆漿粉並添加 3% 葡萄糖之培養基，添加不同蛋白質(豆漿粉、脫脂奶粉)，顯示含有 4.5%豆漿粉為生產 GABA 最佳的培養基。而添加不同氮源(酵母萃 取物、蛋白?、大豆?)實驗，顯示酵母萃取物比其他三種更適合作為生產 GABA 的培養基。添加不同濃度酵母萃取物 3%、6%與 4.5% 進行 B0096 發酵，顯示 4.5%酵母萃取物為生產 GABA 較佳的培養基。最終培養基為 4.5%豆漿粉、3%葡萄糖、4.5%酵母萃取物，以此條件 (4.5% SMP+4.5% YE+3% G)，接種 B0014、B0059、B0096、B0137乳酸菌培養於 37°C，48hr，結果顯示，B0096 產生之 GABA 含量較高。之後以 4.5%豆漿粉、3%葡萄糖、4.5%酵母萃取物培養基加入 1% 蛋白?水解 1 小時，接種 B0096 測定 GABA 含量，顯示經蛋白?水 解具有較佳產率；添加 1% MSG 於 4.5%豆漿粉、3%葡萄糖、4.5% 酵母萃取物培養基並以 1%蛋白?水解 1 小時，接種 B0096 測定 GABA 含量，結果顯示添加 MSG 無法有效增加 GABA 含量。以 4.5%豆漿粉、3%葡萄糖、4.5%酵母萃取物培養基加入 1%蛋白?水解 1 小時，接種 B0096 後 37°C 培養 48 小時，進行凍乾實驗，進行 HPLC 分析 其 GABA 含量，無添加賦形劑 GABA 為 12.8 ± 1.9 g/100g，產率為 16.13%；有添加賦形劑僅 5.20 ± 1.14 g/100 g，產率增加為 52.60%。
B0014, B0059, B0096 and, B0137 have been investigated and have the function of lowering blood pressure. Therefore, these four strains of lactic acid bacteria were further studied. The proportion of soybean milk powder in the medium were 4.5% (containing 4.5%yeast extract) and 8%, the results showed that 4.5% milk powder (containing 4.5%yeast extract) medium was the best medium for producing GABA with B0096. Then, the effects of different fermentation times on GABA were tested, the results showed that incubation at 37°C for 48hr was the best fermentation time for producing GABA. 4.5% soybean milk powder containing 4.5%yeast extract as base medium, different carbon sources (glucose, brown sugar, sucrose) were added and inoculated with B0096, cultivate at 37°C for 48 hours, from the test, addition 3% glucose into the medium for the production of GABA is better than other sugars. 4.5% skim milk powder was added to substitute for 4.5% soy milk powder, we found that 4.5% soy milk powder is still the best medium for producing GABA. Different nitrogen sources (soy peptone, peptone, yeast extract) were added into 4.5% soy milk powder containing 3%glucose. The yeast extract was shown to be more suitable for the production of GABA than the others. 3%, 6% and 4.5% of the yeast extract were tested, it was found that 4.5% yeast extract is the preferred medium for producing GABA. The final medium composition formula were 4.5% soy milk powder, 3% glucose, 4.5% yeast extract (4.5% SMP+4.5% YE+3% G). Using this medium formula, B0014, B0059, B0096, B0137 were inoculated, and incubated at 37°C for 48 hours, the results showed that the content of GABA produced by B0096 was higher than other strains. Followed using 1% protease to hydrolyze the 4.5% soy milk powder, 3% Glucose, 4.5% yeast extract medium for 1 hour, and then inoculated B0096. lt was found that GABA content was higher after hydrolysis treatment. GABA lyophilization experiments were carried out under the same condition and ground into powder, the GABA content was analyzed by HPLC. When no excipient was added, GABA content was 12.8 ± 1.9 g/100g and the yield was 16.13% ,whereas, the addition of excipient ,GABA content was 5.20 ± 1.14 g/100g and the yield was 52.60%。 |
