紅藻所含的洋菜經洋菜分解酵素 (agar-degrading enzyme, ADE) 水解生成的洋菜寡糖（agar oligosaccharides），近年研究已證實洋菜寡糖具有許多保健功效。本研究自海岸養殖九孔取出腸胃道，將其均質液分離出具有胞外型ADE的菌株，經篩選後有四株分別命名為KMU04、KMU06、KMU07與KMU14，四者皆可在以洋菜為單一碳源的培養液生長。四株經培養特性研究後，發現KMU14的ADE有較高比活性，因此以KMU14進行進一步研究。KMU14其生長溫度範圍為30~35℃，生長pH值為7~9，生長鹽度為1~3%。以薄層色層分析發現KMU14的ADE可分解agar、 agarose、 neoagarohexaose、neoagarotetrose，或neoagarobiose生成洋菜寡糖產物。另一方面，為了使KMU14之ADE獲得最大產量，本研究以反應曲面法（response surface methodology, RSM）的central composite design, (CCD) 實驗設計，將KMU14生產ADE最適化的培養溫度（oC）、鹽度（%）、洋菜濃度（%）與通氣量（air/medium ratio, v/v），四者依序為34 ℃、1.75%、0.35%與8等。KMU14經最適化條件培養後，ADE活性比最初提高80.6%。此外，這研究結果可提供量產型發酵槽進行ADE生產時KMU14之建議培養條件。

This study investigated the microbial strains with extracellular agar-degrading enzymes (ADE) isolated from the gastrointestinal tracts of locally cultivated small abalones. We found that four strains, namely KMU04, KMU06, KMU07 and KMU14, were able to utilize agar as the sole carbon source. KUM14 showed the highest specific activity among four strains; therefore, KUM14 was selected to conduct subsequent experiments for ADE production. We found that KUM14’s optimum growth temperature, pH and salinity ranged 30~35 ℃, 7~9, and 1~3 %, respectively. Thin-layer chromatography (TLC) analysis demonstrated that the ADE was able to digest agar, agarose, neoagarohexaose, neoagarotetrose, or neoagarobiose into oligosaccharides. In order to optimize the production of KMU14 ADE and further scale up this fermentation procedure, a statistical RSM (response surface methodology) method with central composite design (CCD) was employed. KMU14 was firstly conducted with bottle-swerving tests for its incubation condition optimization. The optimized incubation temperature (℃), salinity (%), agar concentration (%), and air/medium (v/v) ratio were 34 ℃, 1.75 %, 0.35 % and 8, respectively. The optimized incubation condition for KMU14 ADE activity increased 80.6% than that of initial state. In addition, the result might suggest ADE production conditions for a scale-up fermentor.