利用鳳梨廢汁生產檸檬酸之研究

Studies on Citric Acid Production from Pineapple Waste Juice

本篇報告是以鳳梨罐頭工廠之廢液（鳳梨皮蕊汁）為原料，就著者之一所分離之黑麴菌（Black Asper gillus）進行檸檬酸醱酵之節選試驗。結果發現NTU-143菌株之產酸力最強，該菌株經過菌學性質之鑑定，認為與Asper gillus usamii類似。其最適生產條件如下：1.培養基係將原料鳳梨皮蕊汁濃縮至糖濃度為14%後，以CaCO3處理，除去濃縮液中之檸檬酸鈣，此時濃縮液之pH為5.0。對此經前處理之濃縮液添加甲醇3%及黃血鹽0.03%，然後用之進行醱酵。2.培養時最適接接種量為每1ml培養基中接入3.3×10^3個孢子數，於30℃靜置培養7天。以上述培養條件培養結果，檸檬酸之收率可達對原料糖分之56.3%，對消耗糖分之70%。另以大型醱酵皿作擴大試驗，確認其生產能力，且檢討利用菌蓋進行連績醱酵之可能性。

The strain NTU-13 producing citric acid in a high yield from pineapple waste juice was isolated and was identified with the variety of Aspergillus usamii. In this paper, the optimal culture conditions for the production of citric acid were investigated. 1. Medium: The waste juice was concentrated to 14% of sugar content and calcium carbonate or calcium hydroxide was added to neutralize the citric acid which contained in the juice. Then, calcium citrate precipitate was filted. 3% of methanol and 0.03% of potassium ferrocyanide were added to the concentrated juice as medium. Initial pH of the medium was 5.0. 2. Culture conditions: The optimal inoculum size was 3.3×10^3 spores per ml of medium, and the surface cultured medium was incubated at 30℃ for 7 days. Under the above conditions, the yield of citric acid was 56.3% based on the total sugar supplied, and 70% based on the consumed sugar. Moreover, the experiment with fermentation pan was carried out. The productivity of citric acid was certain, and the continuous fermentation with mycelial mat had also been studied.