PRODUCTION Of NUTRIENT SOURCES FOR RHIZOBIUM

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Metshnikowia (Pitt and Miller, 1968); many strains of Pichia sporulate on malt agar. Some strains of
Zygosaccharomyces rouxii are reported to sporulate best on media containing 2% sodium chloride
(Kreger-van Rig, 1984)). Sporulation of many strains of the genus Lipomyces was favored by dilute
media at low temperature (15-20°C). Temperature could affected ascus formation markedly.
Temperatures between 20 and 25 °C were suitable for most yeasts. Nevertheless, strains of
Debaryomyces hansenii generally sporulate best at 20°C or slightly lower, and many strains of the
genus Metschnikowia required temperatures between 12 and 17 °C (Kurztman and Fell, 1998).
Some yeasts sporulate rapidly, i.e. within 48 hours, especially when first isolated
others might required much longer, up to 6 weeks or more. The ability to sporulate sometimes
declines when a strain was maintained in the laboratory, and might even be lost altogether. This
occurs rapidly in some isolates, perhaps after 2 or 3 subcultures, whereas other strains might be kept
for many years without any apparent decline in their ability to form spores.
Seven yeast isolates, Y69, KAY1, PIY4, PUY4, LIY2, COY1, and FAY2 were
characterized by morphological, physiological, and biochemical. Based on those data their genus or
species was predicted (Table 21). The yeast isolate Y69 showed the data most likely to species
Saccharomycopsis fibuligera, KAY1 belonged to the species Rhodotorula glutinis, PIY2 most likely
to species Zygosaccharomyces bailii, PUY4 most likely to species Candida guiliermondii var.
membranifaciens. Three yeast isolates LIY2, COY1, and FAY2 has the characters of the genus Pichia
in physiological. Chemo-taxonomic properties also suggested that two isolates were LIY2 and COY1
belonged to the species Pichia cactophilla and Pichia pastoris, respectively. Isolate COY1 most likely
to three species, Pichia kluyveri var. eremophila, Pichia membranifaciens, and Pichia toletana.
Table 20. Identification results of yeast isolates.
Isolated number Posibility of genus and species
Y69 Saccharomycopsis fibuligera
KAY1 Rhodotorula glutinis
PIY2 Zygosaccharomyces bailii