酒精发酵凝集性酵母菌的筛选

研究了酒精发酵凝集性酵母菌的筛选方法.通过分离纯化、凝集性试验和发酵试验,从酒精生产酵母菌saccharomycete中筛选出①-4、①-5两株凝集性和发酵能力较强的菌株.经摇床培养,间歇厌气间歇酒精发酵和间歇通气酒精发酵试验证明①-5是具有良好的凝集性的发酵能力强的菌株.     

“珠研”2~＃菌株缩短发酵周期的生产性试验研究（初报）

经诱变、筛选处理的“珠研”２~＃菌株经小试、中试证明其啤酒发酵性能比原引进的菌株有较大的优越性。为验证此菌株对麦汁及扩大生产的适应性，我们对此菌株进行生产性扩大试验。实践证明，“珠研”２~＃菌株对麦汁及扩大生产适应性较强。该菌株具有发酵温度高、降糖快、双乙酰还原能力强、酵母凝集性好、发酵周期短、生产的啤酒质量优越等优点。取得与小试、中试基本一致的结果。我们认为“珠研”２~＃菌株啤酒快速发酵新工艺，可望有良好的推广应用前景。     

双乙酰还原性好的酵母菌株的选育

应用微生物稀释培养法,对生产现场酵母进行了筛选和纯化培养,选出双乙酰还原性能好的酵母菌株。对该菌株进行了相关发酵力分析,并进行发酵成品品尝。最后确定双乙酰还原好的酵母菌株用于生产上,达到理想的效果,从而提高了啤酒风味稳定性。     

筛选优良酵母提高啤酒的发酵度

以青岛酵母为出发菌株，进行单细胞分离培养，通过细胞形态大小测定、低温发酵能力测定、凝聚力测定、EBC发酵测定和死灭温度测定，得出12#为啤酒发酵的优良菌株；该菌株用于大生产，性能良好，可提高啤酒发酵度和啤酒质量。     

东北发酵食物中乳杆菌的研究

从深受人们喜爱的东北发酵食物中分离培养乳杆菌。采用MRS选择性培养基,通过平板稀释培养和溶钙圈方法分离培养并进一步纯化,得到单一的乳酸杆菌菌种,对其进行生化反应鉴定以及16S rDNA序列同源性分析,同时测定耐酸性、疏水性、自凝集性,并进行统计学分析。根据菌落特征、镜下形态特征及生化反应结果,鉴定筛选出的四株菌株,分别为米酒乳杆菌、植物乳杆菌、鼠李糖乳杆菌及短乳杆菌,其耐酸性、疏水性、自凝集性存在差异且差异有统计学意义。东北发酵食物中存在不同种类的乳酸杆菌,其生理特征不同。该研究为进一步研制益生菌制剂及其功能奠定基础。     

生产过程中酵母优选方法的探讨

1.前言酵母是啤酒生产的灵魂。保持接种酵母旺盛的发酵能力是保证啤酒质量稳定的前提。生产用酵母菌株退化问题,经常使啤酒生产厂家感到头疼。菌株退化表现为:起发迟缓、发酵力衰退、发酵度降低、双乙酰峰值升高、还原慢、饮用后易上头等。我公司自1994年开始,在生产过程中对生产用酵母菌株进行优选,保持了菌种的优点,为保持质量稳定、降低消耗,奠定了基础。     

陕西黄桂稠酒酒曲优良菌株选育研究

本文以八种酒曲进行了菌株分离、纯化和复壮研究。选育出了一株糖化酶活力高的报写和二株发酵力强的酵母菌，并研究了它们的主要生产性状。     

高发酵度啤酒酵母生产试验研究

高发酵度啤酒酵母生产试验研究王佐民，索晓光，胡晓东（黑龙江省轻工业研究所）（黑龙江省食品工业公司）啤酒发酵度的高低，啤酒酵母是关键。为了制作高发酵度啤酒，我们采用生物技术，选育分离出１株高发酵度啤酒酵母菌株ＳＬ－８。该菌株具有双乙酰还原能力强、发酵度...     

传统富源酸菜中优质乳酸菌的筛选及应用

以传统自然发酵的富源酸菜为研究对象，利用MRS-CaCO3固体培养基中分离纯化菌株，经过革兰氏染色、过氧化氢酶试验初步鉴定，进行发酵性能（产酸速度、产酸量、降解亚硝酸盐能力、耐酸生长、耐盐生长）测试以确定最优菌株，再通过16S rDNA序列分析进行最终鉴定，并应用于酸菜发酵。结果表明：分离纯化的4株乳酸菌，发酵性能有所差异，菌株N1表现突出，经鉴定为乳杆菌属布氏乳杆菌，将其应用于富源酸菜发酵，发酵效果好，能明显缩短富源酸菜发酵周期，降解亚硝酸盐效果突出，可作为富源酸菜标准化生产菌种。     

甘肃牧区传统发酵乳制品中优良乳酸菌的分离筛选

从甘肃牧区传统发酵乳制品中分离筛选适合发酵乳生产的乳酸菌,对分离纯化的乳酸菌进行了发酵性能检测,筛选出产酸快、发酵活力高、凝乳时间短、后酸化能力弱、遗传性状稳定的菌株。筛选的6株菌株单菌发酵牛乳,均在6.5 h内凝乳,发酵乳酸度70°T,乳酸菌活菌数1×10~8 CFU/mL,发酵乳组织状态、滋味、气味等感官指标良好,可作为生产发酵乳的优良乳酸菌菌种进行开发利用。     

Construction of recombinant industrial brewer’s yeast with lower diacetyl production and proteinase A activity

The characteristic buttery taste of diacetyl has long been a major problem in the brewing industry, and the foam stability of unpasteurized beer is often influenced by proteinase A (PrA), which is encoded by PEP4 and released from yeast cells into beer during brewing. A recombinant industrial brewer’s yeast strain that reduces the diacetyl content of beer and improves foam stability was constructed. We constructed a PGK1p-ILV5-PGK1t expression cassette, which was introduced into one of the PEP4 alleles via PCR-mediated homologous recombination. Then, the second PEP4 allele was disrupted using the Cre-loxP recombination system, and the recombinant strain was designated as S-CSIK12. The results show that the diacetyl production of S-CSIK12 is always lower than that of the host strain at all stages of beer fermentation. In addition, brewing with S-CSIK12 reduced the PrA activity of the final beer by 44 % compared with that using the wild-type strain. The head retention of the beer brewed with S-CSIK12 (260 ± 2 s) was better than that of the host strain S-6 (212 ± 3 s). Considering that more PrA is released from yeast cells during the final stage of main fermentation and that the timing of yeast cropping is determined by diacetyl reduction, brewing with strains that have low diacetyl production also reduced the PrA activity of the beer and improved its head retention. The present study provides reference for the brewing industry as well as research on the diacetyl reduction and foam stability of beer.     

Optimisation of High Gravity and Diet Beer Production in a German Brewery by Flow Cytometry

Increasing the quantity of beer production without diminishing the quality of the product is a key concern of the beer producing industry. Modifications to the brewery's equipment and settings are the most commonly used methods to improve the brewing process, while the supreme importance of the physiological state of the beer producing organisms, the yeast cells, for the productivity of the brewing process is often poorly recognised. The work described here was designed to optimise two processes: the inoculation regime used to produce high gravity bottom-fermenting beer, and the production of high quality diet beer. To achieve these aims, flow cytometry was used to follow changes in the distribution of DNA, neutral lipid and 3β-hydroxsterol contents in Saccharomyces carlsbergensis strains during inoculation, fermentation and storage. This allowed potential time-saving alterations in the process to be identified. Double staining techniques proved that vigorous fermentative activity and long-term survival capacity during main and secondary fermentation requires intense multiplication of the yeast cells during inoculation. The production of high gravity beer was then enhanced by altering the schedule of the wort additions, and thus increasing the yeast's activities related to multiplication. To produce diet beer, oligosaccharides that remain after the standard brewing process are degraded by adding small amounts of wort, usually during secondary fermentation. However, during this period of fermentation the physiological activity of the yeast cells is hampered by low carbon and high ethanol concentrations. Adding small batches of wort at carefully defined time points and in optimised amounts, even during the main fermentation, improves the physiological state of the yeast cells and rapidly decreases the carbon concentration within the fermentation tank. Both of these factors help to promote quick fermentation to a high quality diet beer. Thus, the flow cytometric investigations provided a reliable basis for identifying effective means of improving the process regime for brewing both of these products.     

安琪啤酒活性干酵母在啤酒生产中的应用

安琪啤酒活性干酵母是湖北安琪酵母股份有限公司运用现代生物高新技术开发出的新一代啤酒酵母菌种，具有耐高温、耐乙醇、耐高渗透压等特点。经多次实验证明，此菌种可在不同的发酵起始温度下发酵生产啤酒，便于生产工艺控制，弥补了传统啤酒生产工艺的不足，提高了生产效率，降低了生产成本。     

“SP-3”与“SP-2”在全小麦啤酒酿造中应用研究

“SP-3”是新选育的啤酒酵母菌株,而“SP-2”为通常生产大麦芽啤酒使用的啤酒酵母菌株,“SP-3”与“SP-2”啤酒酵母菌株在全小麦啤酒生产中应用对比试验结果表明,“SP-3”啤酒酵母菌株在全小麦芽啤酒的酿造中适用性较强,各项指标均优于“SP-2”啤酒酵母菌株,用其酿制的啤酒口感纯正、清爽、柔和,能够较好地适应当前消费者的口感需求.     

果酿啤酒的酿造工艺和品质研究进展

果酿啤酒的品质受众多因素影响,特别是水果特性差异和产品质量标准缺失使得果酿啤酒的酿造工艺存在较大差别,产品质量难以稳定。为进一步提升果酿啤酒品质,该文对近年来果酿啤酒的研究现状进行综述,探讨水果榨汁处理、灭菌方式,发酵过程中原麦汁浓度、主发酵温度、果汁添加量及添加阶段、酵母菌种选择等因素对果酿啤酒品质的影响,分析果酿啤酒的风味成分及风味劣变、活性成分及抗氧化活性,并对果酿啤酒的发展趋势及品质提升进行展望,以期实现不同果酿啤酒的精准调控,为实际生产中果酿啤酒的酿造提供借鉴。     

喀麦隆传统Bili啤酒酿造过程及其发酵酵母菌的分类鉴定

该文对喀麦隆传统Bili啤酒的酿造过程及其主要化学组成进行了分析和调查研究。并从各地Bili啤酒酒样中分离酵母菌 3 1株。根据各酵母菌株的生物学特性对其进行了分类与鉴定。发现这些酵母菌分属于Saccharomyces ,Candida ,Kluyveromyces和Pichia等四个属 ,其中以Saccharomyces属的酵母菌为参与喀麦隆Bili啤酒酿造的主要酵母菌种。     

Mutagenizing brewing yeast strain for improving fermentation property of beer

A brewing yeast mutant with perfect sugar fermentation capacity was isolated by mutagenizing the Saccharomyces pastorianus transformant, which carries an integrated glucoamylase gene and has one copy of non-functional alpha-acetolactate synthase gene. The mutant was able to utilize maltotriose efficiently, and the maltotriose fermentability in YNB-2% maltotriose medium increased from 32.4% to 72.0% after 5 d in shaking culture. The wort fermentation test confirmed that the sugar fermentation property of the mutant was greatly improved, while its brewing performances were analogous to that of the wild-type strain and the characteristic trait of shortened beer maturation period was retained. Therefore, we believe that the brewing yeast mutant would benefit the beer industry and would be useful for low caloric beer production.     

Construction of recombinant industrial <Emphasis Type="Italic">S. cerevisiae</Emphasis> strain with barley lipid-transfer protein 1 secretion capability and lower PrA activity

Beer barley LTP1 in beer is an important component of beer foam, and it participates in the formation of beer foam. The digestion of beer barley LTP1 by proteinase A from brewing yeast leads to the decline of beer foam stability, especially for the unpasteurized beer. The objective of this study was to construct an industrial brewing yeast strain to secrete recombinant barley LTP1 into fermenting wort during beer fermentation for the foam stability improvement. We constructed barley LTP1 expression cassette and transformed into the host industrial yeast cells to replace partial PEP4 alleles using homologous recombination method. The expression of b-LTP1 was under control of the constitutive yeast ADH1 promoter, and the concentration of recombinant barley LTP1 secreted by recombinants reached 26.23 mg/L after incubation in YEPD medium for 120 h. The PrA activity of the recombinant strain declined compared with the host strain. The head retention of beer brewed with the recombinant industrial strain (326 ± 12 s) was improved when the host strain WZ65 (238 ± 7 s) and the constructed strain S.c-P-1 (273 ± 10 s) with partial PEP4 gene deficiency were used as control. The present study may provide reference for brewing industries and researches on beer foam stability.     

改进酿酒酵母谷物发酵性能的诱变研究

酿酒酵母经诱变获得有效利用麦汁糖的优良性能。突变菌株经5d摇床培养使YNB基础培养基的麦芽三糖发酵度从32.4%提高到81.8%。薄层层析证明突变株麦芽三糖转运能力得到改善。模拟工业发酵实验证明突变菌株的麦汁糖发酵性能大大改善,而原有发酵优良性状未受到影响。说明该突变株益于工业啤酒生产和低热啤酒的生产。     

Formation of 4-vinyl and 4-ethyl derivatives from hydroxycinnamic acids: Occurrence of volatile phenolic flavour compounds in beer and distribution of Pad1-activity among brewing yeasts

This work represents a survey of the occurrence of hydroxycinnamic acids and volatile phenols in a variety of beer styles. The contribution of 4-vinylguaiacol to the overall flavour perception of top-fermented specialty beers was shown. Significant differences in hydroxycinnamic acids (both free and ester-bound) and volatile phenol content between different beers were observed. The variability in volatile phenol content between different beers and beer styles can be explained by the high incidence of Pad1⁺ phenotype and the variability of Pad1 activity observed among top-fermenting brewing yeast strains. The relative importance of thermal versus enzymatic decarboxylation can account for the differences found between bottom and top-fermented beers. Concerning the optimisation of volatile phenol levels in beer, the selection of a suitable brewing yeast strain is the most important means of creating a phenolic taste profile in beer. Given that a considerable amount of hydroxycinnamic acids in beer still occurs in ester-bound form, enhancing the enzymatic release of these phenolic flavour precursors during mashing can greatly enhance the phenolic aroma potential of wort.