The fermentation products and bacterial population in the rumen were examined in an experiment designed as a 5×5 Latin square, with five Holstein heifers fed five rations differing in ratios of rolled barley to hay (1:0, 3:1, 1:1, 1:3, and 0:1). The proportion of volatile fatty acids (VFA) in the rumen changed drastically when the percentage of barley exceeded 75%. The total and viable counts of rumen bacteria were higher with a high-barley diet. Selenomonas ruminantium, anaerobic lactobacilli, Peptostreptococcus, and Bifidobacterium were most prevalent in the rumen of heifers fed an all-barley diet. Succinivibrio dextrinosolvens was most frequently isolated from animals fed a ratio of 3:1 barley to hay. On the other hand, Butyrivibrio, Ruminococcus, and Bacteroides ruminicola were the most numerous of the bacteria from heifers fed a high proportion of hay. Also, the relationship between the bacteria dominant with each ration and their activities are discussed.
The effect of inoculum preparation on the fully-aerated batch growth of Saccharomyces cerevisiae on glucose is described. The time allowed for inoculum adaptation and the conditions under which adaptation occurred, were observed to have a significant effect on the major metabolic variables: growth rate, specific sugar uptake rate, specific ethanol production rate, specific oxygen uptake rate, specific carbon dioxide production rate, the biomass yield, and the ethanol yield. Adaptation was allowed to occur under conditions of limited aeration (in shake flasks) and under defined aerobic conditions (DOT>75% saturation). With increasing time, differences in the extent of fermentation and respiration were found. Adaptation in shake flasks resulted in a significant increase in the fermentation capacity of the yeast, while adaptation under strongly aerobic conditions resulted in an increase in the respiratory capacity. These results suggest that inoculum preparation is a significant variable which can be manipulated to obtain varying growth characteristics under fully aerobic batch growth conditions.
Two new species of ballistospore-forming yeasts, Sporobolomycesgriseoflavus and Sporobolomyces sasicola, were isolated from dead leaves of Sasa sp. collected on a mountain in Japan. They form pale colored colonies and bilaterally symmetrical ballistospores, have Q-10 as the major ubiquinone and do not contain xylose in the cells. The taxonomic relationship of these new yeasts to Sporobolomyces singularis are discussed.
One hundred and one strains of ballistospore-forming yeasts isolated from 48 samples of dead leaves of a weed, Miscanthus sinensis, were identified as 16 species in the genera Bullera, Sporobolomyces, and Tilletiopsis: Forty-six of 51 strains of Bullera were assigned to B. megalospora (18 strains), B. crocea (15 strains), B. alba (3 strains), B. piricola (3 strains), B. oryzae (3 strains), B. pseudoalba (3 strains), and B. derxii (1 strain). Five strains resembled unidentified yeasts isolated from the dead leaves of Oryza saliva. Forty-one of 47 strains of Sporobolomyces were assigned to Sp. Roseus (37 strains), Sp. Salmonicolor (2 strains), and Sp. Shibatanus (2 strains). Four strains represented 3 new species and were described as Sp. Miscanthi (2 strains), Sp. Subroseus (1 strain), and Sp. weijmanii (1 strain). These new species had Q-9 as the major ubiquinone. The remaining 2 strains of Sporobolomyces represent a single species, still unidentified. Three strains of Tilletiopsis were assigned to T. lilacina. The frequency of isolation of each species from Miscanthus sinensis is compared with that from Oryza sativa.
The ubiquinone systems of 20 strains assigned to the black yeast genera Phaeococcomyces, Exophiala, Hortaea, and Rhinocladiella, and the related genus Cryptococcus were determined by high performance liquid chromatography. The strains tested had ubiquinone systems. The taxa were divided into two groups within the respective genera based on the ubiquinone system, each having the Q-10 or Q-10 (H2) system as the major ubiquinone. The monotypic genus Hortaea had the Q-10 (H2) system, whereas two Cryptococcus species, C. ater and C. magnus related to Phaeococcomyces, had the Q-10 system. The heterogeneity of the ubiquinone profiles suggests that the genera Phaeococcomyces, Exophiala, and Rhinocladiella be revised taxonomically on the basis of the modern taxonomic criteria.
Eighty yeast strains were isolated from 39 samples of 29 kinds of fermented foods (fish, shrimp, meat, cereals, fruit, etc.) and other related materials in Thailand, and identified by conventional and chemotax- onomical methods. These strains were identified as Debaryomyces hansenii var. fabryi (1 strain), Pichia anomala (3 strains), Pichia farinosa (2 strains), Pichia membranaefaciens (1 strain), Pichia ohmeri (1 strain), Saccharomyces cerevisiae (9 strains), Saccharomycopsis fibuligera (2 strains), Stephanoascus ciferrii (1 strain), Candida guilliermondii (4 strains), Candida kefyr (1 strain), Candida krusei (34 strains), Candidamembranaefaciens (1 strain), Candida parapsilosis (1 strain), Candidasorbosa (8 strains), Candida sorboxylosa (2 strains), Candida tropicalis (5 strains), Candida valida (1 strain), Candida sp. (1 strain), and Geotrichumcandidum (2 strains). Candida krusei was the most frequently isolated species from the various kinds of fermented foods and other related materials. Candida sorbosa was isolated only from fermented fruit. The distribution of yeast species in these source materials is discussed.