The present study was aimed at polygalacturonase production from Aspergillus nomius MR103 under solid state fermentation. A total of 57 fungal strains were obtained from mangrove soils collected from Gilakaladindi and Malakayalanka of Krishna District Andhra Pradesh. For the isolation of fungi these Soil samples were serially diluted and plated on pectin agar media plates.  Among them, the isolate which showed maximum polygalacturonase activity was selected for this study. This strain was identified as A. nomius MR 103 by 18S rRNA sequences analysis. Pectin rich agro-industrial wastes like apple peel, citrus peel, orange peel, wheat bran, rice bran and sugarcane bagasse were used as substrates for polygalacturonase production by A. nomius MR 103. This strain was inoculated into the nutrient broth containing agro industrial wastes under solid state fermentation and amount of Polygalacturonase production was estimated. Maximum enzyme production of 4.83 IU/mg was recorded at pH 7.0 and temperature 35?C after 7 days of incubation, when orange peels were used as substrate.  Addition of carbon and nitrogen sources to orange peel media improved the Polygalcturonase production. Sucrose as carbon and peptone as nitrogen sources were proved  to be the best for  maximum production of Polygalcturonase by A. nomius MR 103 on orange peel substrate. Utilization of agro-industrial by-products provided the establishment of a cost-efficient and sustainable process for enzyme production.

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Molecular diversity studies of 19 rhizobia isolates from chickpea were conducted using simple sequence repeats (SSR) and 16S rDNA-RFLP markers. Phenotypic characterization with special reference to salinity and pH tolerance was performed. These isolates were identified as different strains of Mesorhizobium, Rhizobium, Bradyrhizobium, and Agrobacterium. Twenty SSR loci of Mesorhizobium ciceri, distributed across the other rhizobial genome, clearly differentiated 19 rhizobial isolates. Analogous clustering supported the results of 16S rDNA sequence-based phylogeny. Analysis of the 16S rDNA sequences from M. ciceri strains revealed that nucleotide variables (signature sites) were located at 20 different positions; most of them were present in the first 820 bp region from 5' terminal. Interestingly, 14 signature sites were located in two main regions, the variable region V1 (nt 527-584), and variable region V2 (nt 754-813). The secondary structure and minimal free energy were determined in these two regions. These results will be useful in characterizing the micro-evolutionary mechanisms of species formation and increase understanding of the symbiotic relationship.

Twenty five (25) rhizobial strains were isolated from root nodules of Vigna trilobata cultivars grew in soils collected from all districts of Andhra Pradesh, India. Five out of 25 rhizobial strains which produced copious amount of Exopolysaccharides (EPS) on Yeast Extract Mannitol Agar (YMA) medium with congo red were identified by sequencing of their 16S rDNAs. The amount of EPS produced by these five strains increased during the first 72 h of incubation but it declined afterwards. The amount of EPS produced correlated positively with increase in mannitol concentration from 1 to 3% (m/v). However, there was a decrease in EPS production when mannitol concentration was equal or higher than 4%. All the five strains studied preferred mannitol and sodium nitrate as the best carbon and nitrogen sources for EPS production. Sinorhizobium kostiense MRR104 produced maximum levels of EPS 892 mg/100 ml when mannitol was used as carbon source, while S. xinjiangense MRR110 produced maximum levels of EPS 377 mg/100 ml when sodium nitrate was used as nitrogen source. Variation among the rhizobial strains in utilization of carbon and nitrogen sources for EPS production was clearly evident from this study. All the strains analysed in the present study can be exploited for production of commercial biopolymer (gum), due to their non pathogenic nature and their ability to produce copious amounts of EPS when compared to strains studied in earlier reports.

In the present study, 20 fungal strains were isolated from tomato rhizosphere of Senegal. Of 20 strains, five showed the chitinolytic activity on chitin agar medium. Of the five strains, NG4 showed the maximum solubilization zone. This strain was identified by preliminary biochemical and 18S rRNA sequencing analysis. Enzyme production started after 3 days of incubation and maximum was observed after 5 days of incubation. Culture filtrate amended with 0.1% colloidal chitin was used in the production medium. The optimum conditions for maximum chitinase activity are -6 days of growth and temperature of 30°C at pH 6.0. The chitinase activity was also influenced by the addition of carbon and nitrogen sources in the production medium.