皖北地区白酒大曲中酵母菌的筛选与鉴定

为了分离筛选功能优良的大曲酵母菌株,采用传统分离培养方法,从皖北某白酒企业春季中温大曲中分离得到89株酵母菌,选择6株优势菌株进行复筛实验。通过菌落特征、细胞形态、生理生化特性等常规分析方法,筛选出生长优势明显,产酒精能力较强的2株酵母菌株（N4、N6）。结合18S-ITS r DNA序列测定和系统发育分析,确定N4为大隐球酵母（Cryptococcus magnus）,N6为近玫色锁掷孢酵母（Sporidiobolus pararoseus）,属于锁掷酵母属（Sporidiobolus）。筛选的2株酵母菌作为皖北地区白酒酵母菌的重要菌种资源,在白酒生产中具有一定的应用潜力。      

Antioxidant Properties of Sparkling Wines Produced with β-Glucanases and Commercial Yeast Preparations

The aim of this study was to evaluate the in vitro antioxidant potential of sparkling wines produced with β-glucanases, autolysated yeasts, yeast cell walls, and purified mannoproteins. Total antioxidant capacity (measured by 2,2-diphenyl-1-picrylhydrazyl [DPPH] radical-scavenging method and ferric reducing antioxidant power [FRAP] assay), and hydroxyl radical-scavenging activity (HRSA) were higher in the wine samples with coadjuvants (in relation to the control wine). The highest values of antioxidant activity were achieved with purified mannoproteins and, in lesser extent, with β-glucanases. Neutral polysaccharides and total proteins were highly and positively correlated with DPPH, FRAP, and HRSA assays. However, correlations between the levels of each different phenolic family and antioxidant and radical-scavenging activities were not found. β-Glucanase and commercial yeast preparations can be excellent coadjuvants to increase the antioxidant properties of sparkling wines. Practical Application: β-Glucanase and commercial yeast preparations can be excellent coadjuvants to increase the antioxidant properties of sparkling wines. The suggested improvement has significant implication for the production of high added value sparkling wines.     

中国酿酒酵母菌的研究--不同酒类酵母筛选与应用纪实(下)

总结了我国50多年来对不同酒类酵母筛选也应用的研究成果，并通过大量翔实的数据详尽地阐释了酒类酵母不同的特性与作用，推出优良菌种，以达到优质高产、节约粮食之目的。酒类酵母分为酒精酵母、生香酵母、威士忌酵母。酒精酵母又分为小曲酒酵母、大曲酒酵母、小麦酒精酵母、甘蔗酒精酵母。四川小曲酒酵母以纳溪109号酵母较优良，黄酒126号酵母次之；大曲酒酵母以1308号较优，AS2．399次之；小麦酒精酵母以1308号酒精酵母较优；甘蔗酒精酵母则以川102号较优。（陶然）     

几种酵母菌添加剂对奶牛产奶量及乳成分的影响

将54头高产中国荷斯坦奶牛随机分为6组，1组基础对照组，5组（A，B，C，D，E）试验组，试验组在基础日粮的水平上添加15g不同型号的酵母菌制剂，预试期2周，正试期为6周。结果表明：不同型号的酵母菌对奶牛产奶量和奶成分有不同程度的影响，其中C和E组奶牛的产奶量分别比对照组有所增加，B和D组的产奶量与对照组相比增加显著（P〈0．05），A组则有所下降；不同型号的酵母菌制剂对牛乳成分也有不同程度的影响，试验组B，D，E组乳脂日产量比对照组有增加，并且差异显著（P〈0．05）；E组乳脂率增加，差异显著；蛋白质日产量除A组无显著性差异（P〉0．05），B，C，D，E组相比对照组都有所增加，其中C和E组相比对照组，差异显著（P〈0．05）；试验组的乳糖、非脂固形物产量与对照组没有显著差异（P〉0．05）；各试验组的所生产牛奶的比重、冰点、酸度与对照组无显著差异，但试验组的酸度除D组外均比对照组有所提高，乳中体细胞数均比对照组低，其中酵母菌C和D能显著减少乳中体细胞数（P〈0．05）。     

Inactivation behaviors of foodborne microorganisms in multi-frequency power ultrasound-treated orange juice

This study established the inactivation kinetic parameters of some pathogenic bacteria including Escherichia coli O157:H7, Salmonella enterica serotypes, and Listeria monocytogenes; and spoilage yeasts namely, Debaryomyces hansenii, Clavispora lusitaniae, Torulaspora delbrueckii, Pichia fermentans, and Saccharomyces cerevisiae in orange juice subjected to multi-frequency Dynashock power ultrasound treatment. All test organisms exhibited a biphasic inactivation behavior with a sigmoidal inactivation curve consisted of an initial inactivation lag, followed by logarithmic linear inactivation. Injury accumulation in the inactivation lag phase was established in acid-adapted bacteria. The time necessary to reduce initial inoculated populations by 5 log cycles (99.999%), T_5D values, significantly increased with acid adaptation. The T_5D of E. coli, S. enterica, and L. monocytogenes increased from 37.64, 36.87, and 34.59 respectively; to 54.72, 40.38, and 37.83 min respectively after acid exposure. Temperature increase due to sensible heat propagation during ultrasound treatment decreased the resistance of the test bacteria. The cocktail of E. coli O157:H7 had significantly greater resistance towards ultrasound treatment (T_5D = 54.72 min) than any of the individual strain (T_5D = 41.48–47.48 min) in the mix. Similar results were found in the composited (T_5D = 60.02 min) and individual species (T_5D = 20.31–59.04 min). The results established in this work provide baseline information on microbial behavior in multi-frequency ultrasound-treated orange juice for establishment of pasteurization process schedules.     

FORMULATION AND TESTING OF CUPRIC SULPHATE MEDIUM FOR WILD YEAST DETECTION

A new differential medium, cupric sulphate medium, used for the detection of wild yeasts has been formulated and tested. This medium suppressed the growth of culture yeasts and supported that of most non-Saccharomyces wild yeasts. It is not suitable for the detection of Saccharomyces wild yeasts. The contaminating wild yeasts in yeast samples and swab samples were easily detected by this medium. Since Lin's medium or modified Lin's medium is suitable for the detection of Saccharomyces wild yeasts, it is suggested that they be used in conjunction with cupric sulphate medium for detecting a more complete spectrum of wild yeasts.     

Determination of emitted airborne microorganisms from a BIO-PAK wastewater treatment plant

Results of a study conducted to assess the degree of airborne microbial contamination generated by a wastewater treatment plant (WWTP) with bioreactor “BIO-PAK” closed treatment system and evaluation of the dispersion of potential pathogens are described. Over the year aerosol samples were collected simultaneously with sedimentation and impact methods from several plant sites and the surroundings. External upwind sites were used as control. Total colony-forming counts of heterotrophic psychrophilic, psychrotrophic, mesophilic, haemolytic bacteria, as well as members of the Enterobacteriaceae family, Staphylococcus, Enterococcus and Pseudomonas genera, actinomycetes and fungi (moulds, yeasts and yeast-like fungi) were determined. Their highest concentrations ranged up to 10¹-10³ CFU/m³ (with the exception of moulds exceeding 2 × 10⁴) were determined in air sampled inside the bioreactor, its vicinity, and near the grate chamber. Higher species diversity of the family Enterobacteriaceae (including Shigella spp., Yersinia enterocolitica, Escherichia coli, Klebsiella pneumoniae ozaenae) in the air sampled inside or near the bioreactor may imply a health risk for staff exposed for longer periods of time. Notwithstanding, no increased emission of the analysed groups of microorganisms, including faecal bacteria, were found outside the WWTP.     

Glucose and Fructose Fermentation by Wine Yeasts in Media Containing Structurally Complex Nitrogen Sources

Glucose and fructose fermentations by industrial yeasts strains are strongly affected by both the structural complexity of the nitrogen source and the availability of oxygen. In this study two Saccharomyces cerevisiae industrial wine strains were grown, under shaken and static conditions, in a media containing either a) 20% (w/v) glucose, or b) 10% (w/v) fructose and 10% (w/v) glucose or c) 20% (w/v) fructose, all supplemented with nitrogen sources varying from a single ammonium salt (ammonium sulfate) to free amino acids (casamino acids) and peptides (peptone). Data suggest that a complex structured nitrogen source is not submitted to the same control mechanisms as those involved in the utilization of simpler structured nitrogen sources, and mutual interaction between carbon and nitrogen sources, including the mechanisms involved in the regulation of aerobic/anaerobic metabolism, may play an important role in defining yeast fermentation performance and the differing response to the structural complexity of the nitrogen source, with a strong impact on fermentation performance.