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Textile dyes are heavily used in factories for coloring different cloth materials. This work was designed to identify microorganisms capable of removing textile dyes, either by biodegradation or by biosorption. We expected to isolate microorganisms adapted to high dye concentrations from sites near textile industry complex. An experiment was conducted to study the efficiency of the isolates in removing textile dyes. The tested dyes were used as carbon and nitrogen sources for isolation of soil and/or water microorganisms capable of removing textile dyes wastes from factories effluent. The results indicated the low efficiency of both bacteria and actinomycetes in clean-up the effluent from the waste dyes in 10-21 days. On the other hand six fungal isolates were obtained by plating factory effluent on Martin's medium and media containing dyes as the sole source of carbon and nitrogen for growth. These isolates fell in two genera, Aspergillus and Trichoderma. Results of these studies revealed the potential capacity of these fungi to decolorize the tested dyes in comparatively short time (2-24 hours) indicating strong efficiency of dye bioremediation by the fungal isolates. Since the process involved is mostly fast interaction between the fungal mycelium and the dye in the media, the possible mechanism could be based on a biosorption of such chemicals on the intact fungal biomass, rather than direct biodegradation of the compounds.

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In a pot experiment with Vicia faba grown in a calcareous soil and fertilized with three rates on superphosphate, inoculation with phosphate dissolving bacteria (PDB) increased P‐uptake and dry weight. The effect of inoculation exceeded that of the fertilization with half of the usual rate. Dry weight and P‐uptake of plants grown in inoculated soils receiving one half of the usual rate of superphosphate were higher than those for plants grown in pots receiving the usual rate of superphosphate in the absence of the inoculation. The usual rate of superphosphate in the presence of inoculation doubled both P‐uptake and dry weight of Vicia faba. However, one half of the usual rate of superphosphate in the presence of inoculation with PDB increased P‐uptake and dry weight of faba plants by one half more than the control.

A total of 96 bacterial cultures were isolated from soil. Seventeen bacterial isolates were selected following their cultivation on solid media containing 100 mg · L −1 carbofuran as the sole source of carbon and nitrogen. Of the 17 isolates, 10F, 11M, 17N, 23B and 26M were specifically chosen because of their relatively higher growth efficiency and genetic diversity based on Box-polymerase chain reaction analysis. These bacterial cultures had 16S rRNA gene sequences that were most similar to Acinetobacter baumannii (10F), Agrobacterium tumefaciens (11M), Ochrobactrum anthropi (17N), Escherichia coli (23B) and Agrobacterium tumefaciens (26M) with 97, 95, 93, 95 and 94% similarity in their 16S rDNA gene sequence, respectively. Degradation rates of carbofuran in soil inoculated with these isolates were 1.9, 1.5, 1.6, 1.7 and 1.6 times, respectively, faster in comparison with uninoculated soil after 10 days of incubation. The maximum degradation rates of carbofuran (45 and 91%) were detected in soil inoculated with A. baumannii (10F) after 10 and 20 days' incubation, respectively. These data indicate that these isolates may have the potential for use in bioremediation of pesticide contaminated soil.

The survival and persistence of three B. japonicum inoculant strains USDA 110, USDA 138 and TAL 379 were studied in a clay loam Nile valley soil. The inoculated field plots in the summer of 1985 were sown with soybean again in 1986 season. No inoculation in the season of 1986 was conducted and the plants were left to nodulate with the persisted cells of the inocula strains applied a year before. The soil had no background of B.japonicum, however, some nodules were formed on the control plants due to the carryover of the strains with water circulation and some other agricultural practices.The results indicate the persistence of all applied inoculant strains until the next planting season in 1986 with strain USDA 110 being higher in the rhizosphere of the plants than the other two strains. The population dynamics of the three strains in both growing seasons followed the same trend with maximum rhizosphere colonization at blooming stage. While strain USDA 110 was as high in 1986 season as in 1985 season, the counts of both strains USDA 138 and TAL 379 were much lower in 1986 season.The significant response to inoculation recorded in the 1985 season was extended to the 1986 growing season. Although nodulation and seed yield still differed significantly in 1986 season from the control uninoculated plots, no significant differences were found among the strains or their mixtures.The results of the competition between the strains in the two seasons showed that strain USDA 110 was more competitive than strains USDA 138 and TAL 379. The competition patterns in the second season were not markedly different from those of the first season. The predominance of strain USDA 110 in nodules was not correlated with a numerical advantage of that strain over other strains in the host rhizosphere.

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A field experiment in silty clay soil was carried out to evaluate the effect of dual inoculation with Rhizobium japonicum and phosphate dissolving bacteria (PDB) on nitrogen and phosphorus uptakes as well as seed yield of soybean. Seed inoculation with PDB before planting did not induce marked enrichment of PDB counts in the rhizosphere. Inoculation with R. japonicum alone increased the dry weight, N‐uptake and seed yield significantly. Further significant increases in P‐uptake and seed yield were recorded by inoculation with rhizobia and fertilization with superphosphate. However, the inoculation with PDB in combination with R. japonicum in the presence of rock phosphate or superphosphate did not show significant increases in dry weight, N and P uptakes or seed yield as compared with the treatments inoculated with rhizobia alone.