异常威克汉姆酵母在白酒酿造中的应用研究

异常威克汉姆酵母（Wickerhamomyces anomalus）是一种产子囊孢子的酵母,广泛存在于各类水果表面及传统酒曲中,该酵母能够分泌β-D-葡萄糖苷酶、β-D-木糖苷酶、α-L-鼠李糖苷酶等多种糖苷酶,并且具有一定的产香、产酯和产酒精的能力,可以显著提升酒体感官品质,是酒醅发酵过程中重要的功能性微生物。该文对异常威克汉姆酵母的来源、对酒类风味的影响及其在酒类酿造中的应用进行综述,并对异常威克汉姆酵母在酿酒中的应用前景提出展望,旨在为筛选优良酵母菌株,优化酒类发酵条件,提高酒体品质提供参考借鉴。     

Exoglucanase‐encoding genes from three Wickerhamomyces anomalus killer strains isolated from olive brine

Wickerhamomyces anomalus killer strains are important for fighting pathogenic yeasts and for controlling harmful yeasts and bacteria in the food industry. Targeted disruption of key genes in β‐glucan synthesis of a sensitive Saccharomyces cerevisiae strain conferred resistance to the toxins of W. anomalus strains BS91, BCA15 and BCU24 isolated from olive brine. Competitive inhibition of the killing activities by laminarin and pustulan refer to β‐1,3‐ and β‐1,6‐glucans as the main primary toxin targets. The extracellular exoglucanase‐encoding genes WaEXG1 and WaEXG2 from the three strains were sequenced and were found to display noticeable similarities to those from known potent W. anomalus killer strains. Accession Nos for WaEXG1 genes for the strains in brackets are JQ734563 (BS91), JQ734564 (BCA15) and JQ734565 (BCU24); for WaEXG2 genes JQ734566 (BS91), JQ734567 (BCA15) and JQ734568 (BCU24), respectively. Copyright © 2012 John Wiley & Sons, Ltd.     

抗鱼肉脂肪氧化的耐冷冻酵母筛选及鉴定

以常见食品为分离材料,采用冻融法对耐冷冻酵母进行富集,采用涂布平板法和平板划线法分离、纯化耐冷冻酵母;并分析这些酵母菌株的生长特性、产气特性、抗鱼肉脂肪氧化特性。获得25 株具有耐冷冻特性的酵母,其中菌株J3、J7、J8、J9、J12、J15、J18、J25低温下发酵力较好,菌株J8、J12、J18抗鱼肉脂肪氧化活性较强,可消减鱼肉中脂肪氧化产物;通过5.8S rDNA测序法及系统发育分析,8 株耐冷冻酵母均鉴定为异常威克汉姆酵母（Wickerhamomyces anomalus）。本研究为开发新型水产品保鲜剂提供了参考。     

一株莴苣内生产香酵母菌的分离、鉴定及挥发性香气成分分析

通过平板划线分离法,从茎用莴苣中分离出一株酵母样真菌,命名为G0901。形态学特征、生理实验以及26S rDNA D1/D2区序列分析表明,该菌株属于Wickerhamomyces属的Wickerhamomyces anomalus。采用GC-MS方法,对该菌株麦芽汁发酵产生的挥发性香气成分进行检测,结果表明：该酵母菌发酵产生的香气组分主要为烯类和醇类,包括柠檬烯、月桂烯、香桧烯、α-蒎烯、罗勒烯、3-甲基-1-丁醇、苯乙醇和2-辛醇等,其中,柠檬烯的相对含量高达20%,这在发酵产香的微生物当中较少存在。因此,G0901菌株的分离为利用微生物高效生产柠檬烯提供了较好的研究材料。     

异常威克汉姆酵母Y-1对模拟固态发酵白酒酒醅理化指标及风味的影响

该研究以自然发酵和添加安琪酵母发酵为对照组,利用模拟固态发酵白酒技术考察异常威克汉姆酵母（Wickerhamomyces anomalus）Y-1对酒醅理化性质、微生物及挥发性风味成分的影响。结果表明,与其他两组相比,发酵结束时,异常威克汉姆酵母Y-1组酒醅水分及酸度更高,淀粉和还原糖的利用更加彻底;酵母数量最多,霉菌和细菌数量最少。从3组酒醅中共检测出52种主要挥发性物质,包括23种酯类、10种醇类、6种挥发性酸类、6种酚类和7种其他化合物。与其他两组相比,异常威克汉姆酵母Y-1组中酯类（3 066.99 mg/kg）及醇类物质含量（1 731.61 mg/kg）显著提高（P＜0.05）,尤其是己酸乙酯、庚酸乙酯、辛酸乙酯、苯乙醇等化合物,此外,在异常威克汉姆酵母Y-1组还检测到愈创木酚等有益因子。     

Species identification of Wickerhamomyces anomalus and related taxa using β‐tubulin (β‐tub) DNA barcode marker

Wickerhamomyces anomalus is used in food and feed processing, although the species has been reported as an opportunistic human pathogen, predominantly in neonates. Neither phenotypic nor the most frequently applied genotypic marker (D1/D2 LSU ribosomal DNA) provide sufficient resolution for accurate identification of this yeast. In this study, the β‐tubulin gene was used for species identification by direct DNA sequencing and as marker in a species‐specific PCR assay. The results showed that all examined W. anomalus strains were clearly distinguished from the closely related species by comparative sequence analysis of the β‐tubulin gene. In addition, the species‐specific primers were also developed based on the β‐tubulin gene, which was employed for polymerase chain reaction with the template DNA of Wickerhamomyces strains. A single 218 bp species‐specific band was found only in W. anomalus. Our data indicate that the phylogenetic relationships between these strains are easily resolved by sequencing of the β‐tubulin gene and combined with species‐specific PCR assay. Copyright © 2012 John Wiley & Sons, Ltd.     

冷胁迫对异常威克汉姆酵母代谢物组的影响

通过甲氧胺、双(三甲基硅烷基)三氟乙酰胺（含1%三甲基氯硅烷）对6 株抗冷冻异常威克汉姆酵母（Wickerhamomyces anomalus）菌株的培养液进行衍生化,采用气相色谱-质谱法测定冷胁迫处理（4 ℃）对6 株耐冷冻W. anomalus酵母代谢物的影响。质量浓度超过10 mg/L的代谢物为49 种,其中糖、糖醇、糖酸、糖苷34 种,反映了W. anomalus复杂的糖代谢能力,且包括大量具有益生元活性的糖类;此外,还含有角鲨烯、百里香酚-β-D-葡萄糖苷、β-羟基-苯丙酸、异长叶烯,表明W. anomalus具有萜类、苯丙素物质代谢途径。采用代谢物组学数据处理方法识别W. anomalus在冷胁迫时的差异代谢物,甘油、角鲨烯、赤藓糖醇、半乳糖、L-抗坏血酸-2,6-二棕榈酸酯、甘露糖、百里香酚-β-D-葡萄糖苷可能是W. anomalus冷胁迫相关的特征性代谢物。本研究可为酵母冷胁迫机制、酵母发酵食品食味品质形成机制、酵母新产品研发提供理论参考。