- 學位論文
秀珍菇(Pleurotus ostreatus)生長特性與酵素活性之研究
Growth Characteristics and Enzyme Activity of Pleurotus ostreatus
摘要
秀珍菇為一種可食用的菇類，並具有豐富的營養價值、生物降解的功能和生物科技的潛力，也是世界三大主要生產的菇類之一，本研究室在探討秀珍菇最適合生長之因子、抗氧化能力以及酵素之分析。結果顯示最適合菌絲體生長的溫度是28℃，最適合的酸鹼度為pH7.0，較好的碳源為蔗糖，其次依序為果糖與麥芽糖。較佳的氮源為酵母抽出物，依序為黃豆粉、麥芽抽出物和蛋白腖。在菌菇的生產期間，其生物轉換率約為52％。秀珍菇子實體在80℃烘箱乾燥下其粉末的甲醇萃取液在7.5mg/ml的濃度下，對DPPH表現出90％的抗氧化能力，冷凍乾燥處理的秀珍菇子實體其粉末的甲醇萃取液在10mg/ml的濃度下，表現出對亞鐵離子最佳的螯合能力（90.81％）。在還原力測定的部分，秀珍菇子實體以80℃烘箱乾燥下其粉末的甲醇萃取液濃度在10mg/ml表現出最佳的抗氧化能力。在共軛雙烯法的測定中，最佳的處理為秀珍菇40℃的乾燥處理後，在濃度7.5mg/ml的甲醇萃取液，有80％的抗氧化能力。酵素表現方面，菌絲體在平板培養時會分泌漆酶、纖維素分解酶以及木聚糖酶。在液態培養時,其蛋白質分泌量從第3天至第14天均有變化。在第3天的時候以使用木糖為基質（4.76±0.18μg/ml ）時表現出最大量的蛋白質，第7天的時候以使用纖維素（4.6±0.2μg/ml ）為基質時表現出最大量的蛋白質，第14天時以使用guaiacol(2166±94μg/ml )為基質時表現出最大量的蛋白質活性。在固態發酵培養的部份，秀珍菇以太空包培養4個月時達到最大的總蛋白質分泌量(2250μg/ml)，液態培養下秀珍菇酵素的分泌最大值分別為木聚糖酶2.8U、纖維素分解酶7.2U、漆酶100.0U。以蓮霧木和芒果木為混合的木屑為基質，對秀珍菇作酵素分泌的測試，當培養三個半月時測得11.7U的木聚糖酶，培養一個月時纖維素分解酶的活性為4.97U，漆酶在培養一個月時達到最大活性853U。
並列摘要
Pleurotus ostreatus is an edible mushroom valued for its nutritional properties, bioremediation properties and biotechnological potential. The oyster mushroom is one of the three mushrooms industrially produced worldwide. Studies on Pleurotus ostreatus optimal growth factors, antioxidant capacity and enzyme assays were performed. It was found that the best temperature for mycelial growth was 28 °C, the best pH was 7; the better carbon sources were sucrose, fructose and maltose. The better nitrogen sources were yeast, soybean, malt and peptone. During mushroom production the biological conversion was around 50%. The oyster mushroom extract obtained from fruiting bodies dried at 80 °C showed 90% antioxidant capacity at a concentration of 7.5 mg mL-1 on 1,1-diphenyl-2-picrylhydrazyl radicals. Freeze dried Pleurotus ostreatus fruiting bodies showed the highest chelating effect upon ferrous ions (90.81%) at a concentration of 10 mg mL-1. For the reducing power, the best antioxidant treatment (48%) was from the mushrooms dried at 80 °C at a concentration of 10 mg mL-1. For the conjugated diene method, the best treatment was at 40 °C with an antioxidant capacity of 80% at a concentration of 7.5 mg mL-1. Mycelial growth in plate assay proved the presence of the laccase, cellulase and xylanase enzymes. In submerged fermentation, protein concentration varied from day 3 to day 14. On day 3 the highest protein secreted was found in the treatment in which xylan was used as the substrate (4.76 ± 0.18). On day 7 the treatment with higher protein secretion was the one in which cellulose (4.6 ± 0.2) was used as substrate. On day 14, the highest protein secretion was in the treatment with guaiacol as substrate (2166 ± 94). In solid substrate fermentation, the highest amount of total protein secreted was quantified when the mushroom cultivation bags were 4 months old (2250 μg mL-1). The highest specific activities in submerged fermentation of Pleurotus ostreatus were, for xylanase: 2.8 U, for cellulase 7.2 U , and for laccase 100 U. For xylanase, the specific activity in wax apple mango sawdust of Pleurotus ostreatus was of 11.7 U at 3 months and a half. For cellulase, the specific activity was 4.97 U at 1 month, and for laccase, the specific activity was of 853 U at one month as well.