| 出芽短梗霉在三种不同氮源的培养基中多糖积累以及形态变化 |
| Production of exopolysaccharides and morphological changes in shake-flask culture of Aureobasidium pullulans grown on three different nitrogen sources |
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| 中文关键词:黑酵母，培养基，普鲁兰多糖，深层培养，化学结构 |
| 英文关键词:black yeast, culture media, pullulan, submerged incubation, chemical structure |
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| 中文摘要: |
| 本研究旨在阐明出芽短梗霉在不同氮源培养基中形态和胞外多糖的积累及化学成分变化。采用摇瓶法培养出芽短梗霉。三种培养基的氮源分别为硝酸钠（培养基1，M1）、硫酸氨、酵母膏（培养基2，M2）和硫酸氨、蛋白胨和酵母膏（培养基3，M3）。M1培养基中，菌丝体和单细胞的生物量积累均比M2、M3低，但胞外多糖的产量则等于甚至略超过M2和M3。在指数生长的前期，白色菌丝体和酵母状细胞状态占优势。指数生长的后期，以厚垣孢子、肿大细胞和黑色菌丝体占优势。胞外多糖都能为茁霉多糖酶水解为麦芽糖和麦芽三糖，说明这些多糖的化学组成都具有 (1?4,1?6) -? 结构的茁霉多糖。但M1中产生的茁霉多糖结构单元为麦芽糖和麦芽三糖，且二者比例相当。M2中茁霉多糖的麦芽糖结构单元明显减少，而M3中144h后麦芽糖结构单元完全消失。这似乎表明氧化性的氮源和低溶解氧水平可能是造成茁霉多糖结构单元同时具有麦芽糖和麦芽三糖的原因。 |
| 英文摘要: |
| In this study, morphological changes and the production of exopolysaccharides (EPS) by Aureobasidium pullulans were determined by growing the fungus in different nitrogen (N) sources media, which included NaNO3 (medium 1, M1), yeast extract and (NH4)2SO4 (medium 2, M2) and yeast extract, peptone and (NH4)2SO4 (medium 3, M3). Less biomass of mycelia and unicells occurred in M1, but EPS production was comparatively similar to those determined in M2 and M3. At early exponential stage, the population of A. pullulans was characterized by the presence of predominant yeast-like cells and unmelaninized mycelia. At late exponential stage, these were substituted by chlamydospores, swollen cells and melaninized mycelia. EPS produced by the fungus in the three N sources were all able to be hydrolysed by pullulanase. The hydrolytic products were maltose and maltotriose from EPS produced in M1 with almost equal molar ratio, but the ratio of maltose was remarkably decreased in M2 and disappeared from M3 after incubation for 144h. These results suggest that the oxidant N source and low dissolved oxygen might be responsible for the co-presence of maltose and maltotriose as structural units of EPS produced by the fungus. |
| 郑维发 卢辉官 彭景. 出芽短梗霉在三种不同氮源的培养基中多糖积累以及形态变化[J]. 菌物学报, 2009, 28(5): 744-749 |
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