Heavy Metals Biosorption from Aqueous Solution by Endophytic Drechslera hawaiiensis of Morus alba L. Derived from Heavy Metals Habitats

The ability of dead cells of endophytic Drechslera hawaiiensis of Morus alba L. grown in heavy metals habitats for bioremoval of cadmium (Cd²⁺), copper (Cu²⁺), and lead (Pb²⁺) in aqueous solution was evaluated under different conditions. Whereas the highest extent of Cd²⁺ and Cu²⁺ removal and uptake occurred at pH 8 as well as Pb²⁺ occurred at neutral pH (6–7) after equilibrium time 10 min. Initial concentration 30 mg/L of Cd²⁺ for 10 min contact time and 50 to 90 mg/L of Pb²⁺ and Cu²⁺ supported the highest biosorption after optimal contact time of 30 min achieved with biomass dose equal to 5 mg of dried died biomass of D. hawaiiensis. The maximum removal of Cd²⁺, Cu²⁺, and Pb²⁺ equal to 100%, 100%, and 99.6% with uptake capacity estimated to be 0.28, 2.33, and 9.63 mg/g from real industrial wastewater, respectively were achieved within 3 hr contact time at pH 7.0, 7.0, and 6.0, respectively by using the dead biomass of D. hawaiiensis compared to 94.7%, 98%, and 99.26% removal with uptake equal to 0.264, 2.3, and 9.58 mg/g of Cd²⁺, Cu²⁺, and Pb²⁺, respectively with the living cells of the strain under the same conditions. The biosorbent was analyzed by Fourier Transformer Infrared Spectroscopy (FT-IR) analysis to identify the various functional groups contributing in the sorption process. From FT-IR spectra analysis, hydroxyl and amides were the major functional groups contributed in biosorption process. It was concluded that endophytic D. hawaiiensis biomass can be used potentially as biosorbent for removing Cd²⁺, Cu²⁺, and Pb²⁺ in aqueous solutions.

Production of a novel halophilic dextranase from a honey isolate, bacillus subtilis NRC-B233 under solid-state fermentation

A GRAM-POSITIVE, sporulating halophilic bacteria, designated NRC-B233, was isolated from the honey produced in Saudi Arabia. It was identified by the 16-23S intergenic region as Bacillus subtilis NRC-B233. Screening of the wastes and agro-products for dextranase production under solid state fermentation showed that corn flour was the best substrate [61.323 U/g]. The optimum conditions for dextranase productions were 37°C, pH 9, 32 hr incubation period, and 200% moisture content. The most favorable nitrogen and carbon sources for enzyme production were 2% peptone and 5% starch [1076.768, 1553.364 U/g]. respectively. A unique character of this isolate is its ability to continuously produce dextranase in the absence and presence of NaCl 5-20 g/l. The addition of 0.175 Mm CrCl[3] increased the dextranase production about 4.5 fold. The enzyme has been partially purified about 112-fold from crude extract by only two purification steps involving ultra-filtration. The purified dextranase showed its maximum activity at pH 9.2 and 70°C. It retained fill activity [100%] at 75°C for one hour. Dextranase activity increased about four fold in the presence of 10% NaCl. On the other hand, CaCl[2] [0.050M], EDTA [0.100M], and KCI [0.100M] had great influence in enzyme activity. The enzyme showed variable degradation effects on different types of dextran and its derivatives. These results suggest that the dextranase secreted by Bacillus subtilis NRC-B233 is industrially important from the perspectives of its activity at across pH range [5.0-100], its thermo-activity in addition to its halophilic character and its ability to degrade different types of alpha-1,4 and alpha-1,6 glycosidic linkages

Growth and yield responses of tomato [lycopersicon esculentum] grown under soilless cultivation to application of azospirillum, azotobacter and nitrogen

THIS STUDY was undertaken to investigate the possibility of using Azospirillum bras/lease and Azotobacter chroococcum applied with inorganic nitrogen to enhance tomato [Lycopersicon escnlentum, Mill] production in soilless systems. The effect of inoculation with A. brasilense and / or Azoto. chroococcum with the application of 75% [of the recommended dose] of N[2] on certain tomato growth parameters [shoot height, number of leaves, and fresh and dry weights of plants] after 30, 60 and 90 days of transplanting were determined. In addition, total yield, mean fruit weight and number of fruits per plant were evaluated in plants inoculated with the two bacteria [separately or in combination] with 75% N[2], and plants inoculated with 75% N[2] [control 1] and 100% N[2] [control 2], Plants inoculated with a mixed inoculum of A. bras/lease and Azoto. chroococcum with 75% N[2] gave the highest values of the growth parameters tested while plants inoculated with 75% N[2] [control 1] gave the lowest. The same treatment also resulted in the highest tomato yield, mean weight and number of fruits per plant followed by plants treated with A. brasilense and 75% N[2]. The responses to the tested biofertilizers on nitrogen, phosphorous and potassium [NPK] uptake, population of diazotrophic bacteria and nitrogenase and dehydrogenase activity of the tested bacteria on the rhizosphere of tomato showed that the mixed inoculum of A. brasilense and Azoto. chroococcum with 75% N[2] gave the highest NPK uptake levels after 30, 60 and 90 days of transplanting. The same treatment gave the highest population of diazotrophic bacteria and dehydrogenase and nitrogenase activity of the tested bacteria compared with the plants inoculated with a single organism or controls. In contrast, control 1 gave the least values among all treatments. This study shows that inoculation of tomato plants with Azospirillum brasilense and Azolobacter chroococcum have a significantly beneficial effect on tomato yield under soilless cultivation