• KSBB Journal
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• v.11 no.4
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• pp.462-469
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• 1996

Biosolubilization of an Australian lignite was investigated by using Streptomyces viridosporus and Poria cocos. In order to solubilize coals effectively they were pretreated by nitric acid both in surface and liquid cultures. The optimum growth pH was 7.5 for S. viridosporus and 4.5 for P. cocos. The effects of various carbon, nitrogen and metal sources on overall solubilization were also studied. Solubility increased with the addition of urea for S. viridosporus, and peptone and tryptone for P. cocos. However carbon and metal sources had little or negative effects on solubilization. Maximum amount of coal solubilized was 85%(w/w) in a batch fermentation culture. Extracellular materials produced by micro-organism were found to be responsible for the coal solubilization. Approximately 70 to 80% of coal solubilization was determined to be the result of non-enzymatic reactions, and the rest to be the result of enzymatic reactions. Characteristics of the solubilized coal were compared with those of original coal and pretreated coal by the approximate and ultimate composition analysis, and IR-spectrum analysis. The spectroscopic results showed that the mechanism of coal solubilization was caused by continuous oxidation.

• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1101-1108
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• 2011

The rise in global energy demand has prompted researches on developing strategies for transforming coal into a cleaner fuel. This requires isolation of microbes with the capability to degrade complex coal into simpler substrates to support methanogenesis in the coal beds. In this study, aerobic bacteria were isolated from an Indian coal bed that can solubilize and utilize coal as the sole source of carbon. The six bacterial isolates capable of growing on coal agar medium were identified on the basis of their 16S rRNA gene sequences, which clustered into two groups; Group I isolates belonged to the genus Rhizobium, whereas Group II isolates were identified as Chelatococcus species. Out of the 4 methods of whole genome fingerprinting (ERIC-PCR, REP-PCR, BOX-PCR, and RAPD), REP-PCR showed maximum differentiation among strains within each group. Only Chelatococcus strains showed the ability to solubilize and utilize coal as the sole source of carbon. On the basis of 16S rRNA gene sequence and the ability to utilize different carbon sources, the Chelatococcus strains showed maximum similarity to C. daeguensis. This is the first report showing occurrence of Rhizobium and Chelatococcus strains in an Indian coal bed, and the ability of Chelatococcus isolates to solubilize and utilize coal as a sole source of carbon for their growth.

• KSBB Journal
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• v.7 no.1
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• pp.73-78
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• 1992

The solubilizations of Australian lignite by the fungus Poria cocos, Trichodermareesei, Candide tropicalis, and niger were investigated. Three different types of chemical pretreatment methods were used for increasing biosolubility of lignite. Nitric acid and hydrogen peroxide were proven to be proper chemical pretreatment materials of Australian lignite. Poria cocos showed much better solubilization ability than other strains. Interpretation of the nature of coal solubilization by Poria cocos was based primarily on infrared, ultraviolet and nuclear magnetic resonance spectrum analyses.