摘要
多醣體（polysaccharides）是由單醣類聚合而成的高分子，其分子量分布廣泛。乳酸菌胞外多醣體是乳酸菌在生長時會分泌到胞外的一種糖類複合物。因其具有抗氧化、抑菌等特性，可作為保健品、保濕劑、穩定劑、增稠劑、凝膠劑外和醫療用血漿替代品等。魏斯氏菌所生產之胞外多醣體主要成份為右旋醣酐（dextran），在食品、生醫與化妝品產業中具有高度商業應用價值。為能提升胞外多醣體生產量，本研究以回應曲面法分別探討菌種生產胞外多醣體的培養條件與培養基組成。藉由中心混成法的進行最適化設計研究，結果顯示將菌株使用最適化培養基（酵母萃取物8.4%和蔗糖11.2%）靜置培養於24.5 oC和pH 6.45的環境，其胞外多醣體產量可達64.79± 0.24 g/L。總體而言，本研究成功以最適化培養環境和簡單培養基提升魏斯氏菌的胞外多醣體產量。
關鍵詞：胞外多醣體、魏斯氏菌、回應曲面法、中心混成法Abstract
Polysaccharides (EPS) are polymers that are polymerized from monosaccharides and have a wide molecular weight distribution. Exopolysaccharide (EPS) from lactic acid bacteria (LAB) is a carbohydrate compound, which is synthesized and secreted to outside of the cell during the cell growth process. Due to its anti-oxidation, antibacterial, and other characteristics, EPS can be used as health care products, water-retaining agent, stabilizer, thickener, gel and medical plasma alternatives.The main component of EPS secreted from Weissellacibaria 27 is dextran and has a high potential of commercial application value in the fields of food, cosmetics, and medical industries.To improve the production of EPS, the response surface methodology was used to study the culture conditions and medium composition.The research of optimization design was carried out by using the method of central composite design.The results showed that the yield of EPS could reach 64.79 ± 0.24 g / L when the strain was cultured in an environment of 24.5 oC and pH 6.45 using an optimized medium (8.4% of yeast extract and 11.2% of sucrose).Overall, the production of EPS was successfully improved by W.cibaria27 with an optimized culture environment and simple medium.
Keywords: Exopolysaccharide, Weissellacibaria, Response Surface Methodology, Central Composite Design