Seven strains were collected for phosphate solubilizing and potassium decomposing activities from Microbiology Laboratory, Department of Biotechnology, Shweziwa Biofertilizer Plant. When phosphate solubilizing activity of selected strains was qualitatively determined, all strains except from B1 strain, gave clear zone formation on NBRIP media. But when quantitatively determined by spectrophotometric method, all strains solubilized insoluble tricalcium phosphate. Among seven strains, Ps strain gave the highest soluble phosphate concentration (386 ppm). Potassium decomposing activity was also determined for qualitatively and quantitatively. For qualitative determination, potassium decomposing activity was screened for clear zone formation on potassium decomposing media. Among seven strains, B1 and Y strains cannot give clear zone around their colonies. But when determined by AAS method, all strains can decompose potassium mica by giving soluble potassium concentration. Y strain gave the highest soluble potassium concentration (8.45 ppm). Phosphate solubilizing and potassium decomposing strains were combined differently for four treatments to study their effects on tomato cultivation. Chemical fertilizer was also applied to compare with selected strains. Among all treatments, T-4 showed better result on total yield although yields were not significantly different.

For effective degradation of agricultural residues into more useful forms, cellulolytic nitrogen fixing bacteria were isolated from soil samples of central region of Myanmar. Among 32 isolated strains, six best isolates (three strains of Azomonas agilis, two strains of Azotobacter chroococcum, and one strain of Alcaligenes sp.) were selected. Best strains were selected by their nitrogen fixing activities. Nitrogen fixing bacteria cannot excrete significant amount of ammonia into their environment. To improve cellulolytic nitrogen fixing activities, Alcaligenes sp. among six isolates was muatgenized with chemical mutagen, MNNG. From treatment of Alcaligenes sp. with three concentrations of MNNG (7.5 ppm, 10 ppm and 12.5 ppm), six potential mutant colonies were obtained. After screening of nitrogen fixing activities of wild type and mutagenized strains, four out of six mutant strains excreted higher amount of ammonium concentration than wild type strain. Although wild type strain of Alcaligenes sp. excreted 46.64 ppm of ammonium concentration, 101.35 ppm of ammonium concentration was excreted by mutant strain (M2-F) of Alcaligenes sp. According to results obtained, 10 ppm of MNNG was more effective for obtaining better mutant strain for nitrogen fixing activity. Although nitrogen fixing activities of mutant strains were increased, cellulolytic activities were decreased than those of wild type strain. Reducing sugar concentrations produced by all mutant strains were decreased using cellulose and CMC as substrates than wild type strain.