Abstract
Isolation and identification of the indigenous yeasts of the rotten date fruits for possible production of bioethanol and singlecell
protein was the aim of this study. Results showed that a considerable amount of date fruits is subjected to unfavorable
conditions of storage that induce their rot and spoilage. From the rotten date fruits, ten yeast isolates were obtained and
genetically identified by the sequence of D1/D2 domain of the 26S rRNA gene and phylogenetic analysis. The identity of
these yeasts was: Hanseniaspora guilliermondii, H. uvarum (2 strains), H. opuntiae, Pichia kudriavzevii (2 strains),
Issatchenkia orientalis, Wickerhamomyces anomalus, Yarrowia lipolytica and Zygosaccharomyces rouxii. The ability of these
strains to ferment 20% of the spoilage date fruit juice evaluated on laboratory scale. Results proved that P. kudriavzevii
KKUY-0151 and H. uvarum KKUY-0153 yielded 67.48 and 67.37 g/L respectively, of bioethanol as the highest producers.
However, H. uvarum KKUY-0078, H. guilliermondii KKUY-0009 and Z. Rouxii KKUY-0157 produced the highest fresh
biomass weight 31.76, 30.96 and 30.69 g/L, respectively as a single cell protein production. The study is a pioneer to
investigate the endemic yeasts of the rotten date fruits. It concludes that some of the indigenous yeasts of the rotten date fruits
are promising organisms in recycling the substrate into valuable products such as bioethanol and single-cell protein.