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Abstract A thermophilic Bacillus strain ASU7 was isolated from soil sample collected from Assiut governorate in Upper Egypt on latex rubber-containing medium at 45 °C. Genetically, the 16S bacterial ribosomal RNA gene of the strain ASU7 was amplified by the polymerase chain reaction (PCR) and sequenced. The sequence of the PCR product was compared with known 16S rRNA gene sequences in the GenBank database. Based on phylogenetic analyses, strain ASU7 was identified as Bacillusamyloliquefaciens. The strain was able to utilize Ficus elastica rubber latex as a sole source for carbon and energy. The ability for degradation was determined by measuring the increase in protein content of bacterium (mg/g dry wt), reduction in molecular weight (g/mol), and inherent viscosity (dl/g) of the latex. Moreover, the degradation was also confirmed by observing the growth of bacterium and formation of aldehyde or keto group using scanning electron microscopy (SEM) and shiff’s reagent, respectively.

Abstract A thermophilic Bacillus strain ASU7 was isolated from soil sample collected from Assiut governorate in Upper Egypt on latex rubber-containing medium at 45 °C. Genetically, the 16S bacterial ribosomal RNA gene of the strain ASU7 was amplified by the polymerase chain reaction (PCR) and sequenced. The sequence of the PCR product was compared with known 16S rRNA gene sequences in the GenBank database. Based on phylogenetic analyses, strain ASU7 was identified as Bacillusamyloliquefaciens. The strain was able to utilize Ficus elastica rubber latex as a sole source for carbon and energy. The ability for degradation was determined by measuring the increase in protein content of bacterium (mg/g dry wt), reduction in molecular weight (g/mol), and inherent viscosity (dl/g) of the latex. Moreover, the degradation was also confirmed by observing the growth of bacterium and formation of aldehyde or keto group using scanning electron microscopy (SEM) and shiff’s reagent, respectively.

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.

Abstract Natural rubber latex is one of the problems that raises the environmental concerns. In this study the degrading ability of Ficus elastica rubber latex by a bacterium strain ASU-03, isolated from Egyptian soil was assessed. The strain was able to produce clear zone around its colony on latex rubber containing medium and was identified by conventional methods as Streptomyces sp. Phylogenetic analysis of 16S rRNA (16S rRNA) and RNA polymerase ß-subunit (rpoB) genes were applied. Results of the 16S rRNA gene analysis revealed that the strain was highly related to Streptomyces sp. (100% similarity), so the rpoB gene was partially sequenced to clarify the specific name of the isolate. Phylogenetic tree based on rpoB gene sequences indicated that strain ASU-03 was highly similar to the reference strain Streptomyces labedae and both were shared a one cluster. The current results demonstrated that the use of a rpoB gene-based method gives a better resolution in the species level identification. To our knowledge, this species has never been reported to be involved in natural rubber degradation. This was therefore the first report about the degradation of Ficus elastic by S. labedae. The degradation of Ficus elastica rubber latex was determined by measuring the increase in protein content of bacterium (mg/g dry wt), reduction in molecular weight (g/mol) and inherent viscosity (dL/g) of the latex. Moreover the degradation was also confirmed by formation of aldehyde or keto group by Schiff’s reagent and by observing the growth of the Streptomyces strain using scanning electron microscopy.

Abstract Natural rubber latex is one of the problems that raises the environmental concerns. In this study the degrading ability of Ficus elastica rubber latex by a bacterium strain ASU-03, isolated from Egyptian soil was assessed. The strain was able to produce clear zone around its colony on latex rubber containing medium and was identified by conventional methods as Streptomyces sp. Phylogenetic analysis of 16S rRNA (16S rRNA) and RNA polymerase ß-subunit (rpoB) genes were applied. Results of the 16S rRNA gene analysis revealed that the strain was highly related to Streptomyces sp. (100% similarity), so the rpoB gene was partially sequenced to clarify the specific name of the isolate. Phylogenetic tree based on rpoB gene sequences indicated that strain ASU-03 was highly similar to the reference strain Streptomyces labedae and both were shared a one cluster. The current results demonstrated that the use of a rpoB gene-based method gives a better resolution in the species level identification. To our knowledge, this species has never been reported to be involved in natural rubber degradation. This was therefore the first report about the degradation of Ficus elastic by S. labedae. The degradation of Ficus elastica rubber latex was determined by measuring the increase in protein content of bacterium (mg/g dry wt), reduction in molecular weight (g/mol) and inherent viscosity (dL/g) of the latex. Moreover the degradation was also confirmed by formation of aldehyde or keto group by Schiff’s reagent and by observing the growth of the Streptomyces strain using scanning electron microscopy.