Isolation of five ionizing radiation (IR)-resistant bacteria by screening of isolates from various habitats classified as common and stressed is reported. IR-resistant isolates exhibited varying degrees of resistance to gamma-radiation and were classified as highly and moderately radiation resistant. Resistance to ultraviolet (UV) radiation correlated well with gamma-radiation resistance, whereas a comparable desiccation resistance for all the highly and moderately radiation-resistant isolates was observed. However, salt tolerance failed to correlate with IR resistance, indicating a divergent evolution of the salt tolerance and radiation resistance. Characterization of isolates by the amplified rDNA restriction analysis profiling attested to the clustering of these isolates with their stress phenotype. 16S rRNA gene-based analysis of the isolates showed that the bacteria with similar-resistance physiologies clustered together and belonged to related genera. Hydrogen peroxide resistance and mitomycin survival patterns of the isolates indicated the roles of oxidative-stress tolerance in desiccation survival and recombination repair in higher radiation resistance, respectively.

No abstract

No abstract

Summary. Two series reactors separately packed with immobilized cells of Saccharomyces cerevisiae BRL-7 producing alcohol and Hansenula anomala producing ethyl acetate were used to produce meads of controlled quality. The rate of alcohol production and the amount of ethyl acetate produced were 6.13 g/h and 61.6 mg/100 ml, respectively, at a dilution rate of 1.36 h-1. Coimmobilized cells of S. cerevisiae BRL-7 and H. anomala produced alcohol at the rate of 8.02 g/h with 40 mg/100 ml ethyl acetate content at a dilution rate of 2.15 h -1. The process of immobilization, use of dual cultures and series reactors reduced the time period of mead production and eliminated the costlier aging process.

No abstract