CLASSIFICATION OF CERTAIN PEDIOCOCCI ISOLATED FROM BREWERY PRODUCTS

New solid and liquid media have been developed for the cultivation of a group of slow-developing pediococci, isolated from brewery products, that have previously proved difficult to cultivate. These media also formed a suitable basis for the production of special media for identification and classification of such pediococci. A physiological and biochemical study indicated that the strains investigated are closely akin to a group of pediococci which by other workers are classified as Pediococcus damnosus.     

DETECTION AND IDENTIFICATION OF LACTOBACILLUS LINDNERI FROM BREWERY ENVIRONMENTS

Ten detection media and six cultivation techniques were evaluated for the detection of a harmful brewery contaminant, for which the name Lactobacillus lindneri was recently revived. These bacteria showed slow and weak growth on solid media. However, enrichment of beer with NBB-C or the use of a mixture of MRS and beer (4:1 v/v) reduced the detection time by 2 days or more, depending on the strain, compared to cultivation on solid brewery media. Eight brewery isolates from different origins, the type strain and a test strain were characterized by carbohydrate fermentation tests (API 50 CHL), by a chemotaxonomical (SDS-PAGE) and by a genomic fingerprinting (ribotyping) method. The results obtained by all these methods indicated that the isolates studied form a single group and can be assigned to the species L. lindneri. However, using the current standard reagents, ribotyping cannot discriminate the strains isolated from different sources .     

DETECTION OF WILD YEASTS IN THE BREWERY EFFICIENCY OF DIFFERENTIAL MEDIA

The efficiency of five differential media in the detection of wild yeasts was compared. On the basis of the types of wild yeast they are able to detect, these differential media were classified into two groups. Group I consists of actidione medium and lysine medium, and is suitable for the detection of non-Saccharomyces wild yeasts. In this group, the lysine medium detected more species and a higher percentage of wild yeasts than the actidione medium. Group II consists of crystal violet medium, SDM, and Lin's medium, and is suitable for the detection of Saccharomyces wild yeasts. In this group, Lin's medium is superior to crystal violet medium and SDM for wild yeast detection. It is suggested that lysine medium and Lin's medium be employed together for the detection of wild yeasts in the brewery.     

IDENTIFICATION OF LACTIC ACID BACTERIA ISOLATED FROM DIFFERENT STAGES OF MALT WHISKY DISTILLERY FERMENTATIONS

A number of strains of lactic acid bacteria were isolated and identified from samples obtained from different stages of malt whisky distillery fermentations. Isolates were subjected to a range of biochemical and physiological tests and results obtained were used to make tentative identifications. The types of lactic acid bacteria associated with a particular stage of the fermentation are discussed. Results obtained suggest that Leuconostoc was the most common bacterial contaminant and tends to die off at the later stages of the fermentation. The most likely sources of bacterial contamination in the distillery are discussed. Results have shown that yeast is a very important source of contamination on an industrial scale.     

AGGLUTINATION TESTS AS AN AID TO THE CLASSIFICATION OF PEDIOCOCCI AND AEROCOCCI

To throw further light on the relationship between pediococci and aerococci, rabbits were immunized with cell antigens from 13 Pediococcus and 12 Aerococcus strains. All the immune sera prepared displayed relatively high agglutination titres. The pediococci from brewery products (11 strains), classified as Pediococcus damnosus, showed 100% mutual serological binding capacity (group binding). If account is taken of all the strains tested, the pediococci displayed a serological group binding of about 86% and the aerococci a corresponding binding of about 73%. All strains agglutinated with their homologous antisera. Of the cross-agglutination tests carried out with Pediococcus antiserum against Aerococcus antigen (about 5% positive) and Aerococcus antiserum against Pediococcus antigen (about 30% positive), an average of about 18% displayed a binding capacity. The pediococci appear to represent a homogeneous serological group, whereas the aerococci are clearly mutually more serologically indifferent. A lack of serological binding capacity, especially between Pediococcus antiserum and Aerococcus antigen, shows that there is a very limited serological kinship between these two groups of bacteria.     

THE FORMATION OF ESTERS AND HIGHER ALCOHOLS DURING BREWERY FERMENTATION; THE EFFECT OF CARBON DIOXIDE PRESSURE

The influence of the size and geometry of brewery fermentation vessels on beer flavour and aroma formation is generally attributed to carbon dioxide pressure. In order to study this pressure effect, brewery batch fermentations were carried out on the laboratory scale with Saccharomyces cerevisiae. The formation rates and yields of esters and fusel alcohols were studied in relation to the growth of metabolically active biomass. The results indicate that the observed reduction in the formation of esters and fusel alcohols with increased carbon dioxide pressure is mainly caused by reduced yeast growth. The overall formation of fusel alcohols is less affected than the formation of esters.     

五种常见野菜Vc含量的测定

The contents of vitamin C of the wild vegetables in the Capsella dursa-pastoris,Portulaca oleracea,Talinm paniculatum,Stellaria aquatica and Sonchus arvensis were determined. The result indicates that the contents of vitamin C of the wild vegetables are very high. Some proposals on the utilization of wild vegetables put forward.     

THE API 20E MICROTUBE SYSTEM FOR RAPID IDENTIFICATION OF GRAM NEGATIVE BREWERY BACTERIA

The API 20E Microtube System and two supplementary media are proposed to identify at least to genus level the Gram negative bacteria of brewing origin. The system has been checked for its utility in breweries by processing 31 verified cultures of brewing bacteria. Results indicate potential advantages of these techniques over more time-consuming traditional methods of biochemical testing especially in smaller breweries where microbiological expertise and time are limited.     

THE DETECTION AND IDENTIFICATION OF PEDIOCOCCUS AND MICROCOCCUS IN BREWERIES,USING A SEROLOGICAL METHOD

A commercially-available antiserum for the identification of group D strains of Streptococcus contains antibodies which react with Pediococcus and Micrococcus, and provides a convenient method to detect these genera in yeast, wort and beer. After suitable adsorption it can be used to distinguish between Pediococcus and Micrococcus and, within each genus, to differentiate between groups normally found in a brewery environment and those from other sources.     

ENTEROBACTER AGGLOMERANS—A NEW BACTERIAL CONTAMINANT ISOLATED FROM LAGER BEER BREWERIES

From a large number of bacterial strains isolated from all stages of the brewing process in four different beer breweries in South Africa, fifty-five bacterial strains were identified as Enterobacteriaceae by phenotypic analysis. All enterobacterial species previously reported in brewery samples, as well as eighteen strains of Enterobacter agglomerans were found. E. agglomerans strains were isolated from pitching yeast and fermenting wort samples. The occurrence of E. agglomerans in pitching yeast is significant and indicates that these bacteria survive the brewing process. E. agglomerans is regarded as a potential beer spoilage contaminant in lager beer breweries.     

PHENOTYPIC PROPERTIES,METABOLIC ACTIVITIES AND ELECTROPHORETIC PROTEIN PATTERNS OF Klebsiella oxytoca AND Klebsiella pneumoniae STRAINS ISOLATED FROM LAGER BEER BREWERIES

Phenotypic properties, metabolic end products and gel electrophoretic protein patterns of indole-negative and indole-positive Klebsiella pneumoniae strains isolated from beer breweries are reported. Results obtained clearly indicate that the indole positive K. pneumoniae strains represent a distinct group of klebsielleae and that they should be placed in a distinct group of Klebsielleae and that they should be placed in a distinct taxon, namely, Klebsiella oxytoca.     

THE DETECTION OF ENTEROBACTER AGGLOMERANS (ERWINIA HERBICOLA) IN BREWERY WORTS BY GAS CHROMATOGRAPHY

A gas chromatographic procedure is described to detect Enterobacter agglomerans, a bacterial contaminant in beer breweries. Ethanol, acetic acid, acetoin and 2,3-butanediol produced by bacteria in a growth medium was used to detect the contaminant at levels as low as three organisms/ml. A correlation was found between the initial numbers of contaminants present and the amounts of volatiles produced.     

益生菌促生长因子的筛选

益生菌是一类能够促进肠内菌群生态平衡，对宿主起到有益作用的微生物制剂，人工培养驯化后方可加以有效利用。在使用培养基对益生菌进行培养时，需要添加适宜的促生长因子，才能使益生菌株良好生长，得到强壮的菌株。本实验试用了一系列促生长因子并加以比较，筛选出适宜的促进益生菌株生长良好的生长因子。     

IDENTIFICATION OF A GROWTH FACTOR IN TOMATO JUICE FOR A NEWLY ISOLATED STRAIN OF PEDIOCOCCUS CEREVISIAE

A newly isolated strain (L-73) of Pediococcus cerevisiae showed very slow growth in the Nakagawa medium which has been routinely used for the detection of lactic acid bacteria in the brewery. When the Nakagawa medium was enriched with 2% tomato juice extract or when the medium was prepared with the use of unhopped beer, strain L-73 showed good growth. The growth-stimulating factor in tomato juice was purified by chromatography on a charcoal column and it was finally identified by bio-autography as 4′-0-(β-D-glucopyranosyl)-D-pantothenic acid.     

沙棘果油中维生素E的色质谱分析

本研究应用柱色谱预分离、气相色谱与质谱联用技术,在国内首次对野生植物沙棘果油中所含的维生素E类组份进行了系统的分析鉴定.除分析出了α、β、γ、δ——生育酚外,还用质谱碎片解析法推断出了四种未有报道的新组份,为沙棘果油在化妆品及医药方面的应用提供了可靠的依据.     

乳酸菌基础培养基比较研究

研究了脱脂乳中性蛋白酶的最适酶解条件，并以保加利亚乳杆菌和嗜热链球菌为混合发酵菌种，对MRS、脱脂乳和脱脂乳酶解液3种基础培养基进行了比较研究。结果表明：（1）脱脂乳中性蛋白酶的适宜酶解条件为：加酶量5000U／g蛋白质，在pH=7．0，50℃下酶解2h；（2）脱脂乳酶解液是保加利亚乳杆菌和嗜热链球菌混合菌种较好的基础培养基，其冻干发酵剂的质量和数量均优于脱脂乳培养基。以脱脂乳酶解液为基础培养基制备的冻干发酵剂的活菌数达到3．5×10^11cfu／g，冻干发酵剂的重量是脱脂乳的1．93倍。     

草莓汁加工贮藏过程中维生素C稳定性的研究

初步考察了影响草莓汁加工贮藏过程中维生素C变化的因素。采用正交试验法,以加工贮藏过程中维生素C的保存率为考察指标,对维生素C的变化进行了初步研究。结果表明,实验设计的三因素中含空气量对维生素C的变化有显著影响。最佳加工贮藏初步工艺为:采用热榨加工工艺,在15-18℃冷室,无氧贮藏方式。为草莓汁的进一步加工贮藏提供了理论依据。