Evaluation of some biophysical characteristics of five silicate solubilizing bacteria isolated from different ecosystems

Silicate solubilizing bacteria (SSB) are key microorganisms to solubilize silicate minerals in the soil. Silicon helps to increase the growth and yield of plants and to enhance the environmental stress tolerance capability of plants. The aim of this study was to evaluate the effect of several factors like pH, salinity, and temperature on silicate solubilizing capacity of five selected SSB. Moreover, phosphorus solubilizing, nitrogen-fixing and indole-3-acetic acid (IAA) synthesizing capacity of these five bacteria were also tested. Liquid soil extract medium containing 0.25% Mg2O8Si3 was used in this study. Abilities of bacteria in phosphorous solubility, nitrogen fixation, and IAA synthesis were tested in NBRIP, Burk’s and NBRIP containing 100 mg L-1 tryptophan media, respectively. The results of the study indicated that five SSB showed their high capacity in silicate solubilization at pH 7.0, NaCl 0.0% and 35oC. However, at a concentration of NaCl 0.5%, these five SSB still solubilized well silicate mineral. Moreover, they also solubilized effectively three different insoluble phosphate sources of Ca3(PO4)2, AlPO4 and FePO4 with a range varied between 105.8 and 928.7 mg P2O5 L-1, 33.9 and 49.6 mg P2O5 L-1, and 1.94 and 34.1 mg P2O5 L-1, respectively. They also fixed biologically nitrogen with a range from 1.37 to 5.09 mg NH4+ L-1 after 2 incubation days. Finally, they also showed their ability in IAA synthesis with an amount between 4.85 and 51.5 mg IAA L-1. In short, these five SSB in this study not only had the ability in silicate solubilization but also had other functions in plant growth promotion.

Enhanced solubilization of insoluble silicate from quartz and zeolite minerals by selected Aspergillus and Trichoderma species

Silicon (Si) is a major component of sand, silt and clay particles of soils. Available silica as silicic acid (H4SiO4) present in soil solution is considerably low, only in the range of 3.5–40.0 mg Si L-1. To improve plant-available Si in the soil, silicate-solubilizing fungi (SSF) are potentially important in solubilizing insoluble forms of silicate (SiO2). The objectives of this study were to determine silicate solubilizing capacity and organic acid produced by seven SSF isolates on Bunt and Rovira media by using 0.25% (w/v) magnesium trisilicate (Mg2O8Si3), quartz, and zeolite as a silica source. Determination of SSF isolates potential in Si solubilization was carried out in a completely randomized design with three silica sources and three replicates. The results indicated that all SSF were capable of producing acetic, citrate, and oxalic acids and enhancing the solubilization of insoluble silicates. Trichoderma polysporum and Aspergillus niger BCCF194 were the best isolates of SSF. Furthermore, there was significantly (p<0.05) positive correlation between solubilizing silicate capacity by using quartz or zeolite as a silica source on Bunt and Rovira media with incubation time (R2 = 0.79-0.99) and citric acid production (R2= 0.97-0.99) from T. polysporum and A. niger BCCF194

Cloning and Functional Analysis of pqq Genes Phosphorus Solubilizing From Bacillus Mycoides Gnyt1

[Background]The pqq genes which encodes phosphorus solubilizing from Bacillus mycoides Gnyt1 has been cloned and characterized. The role of this action on the function of pqq genes were detected. The phosphorus soluble pqq genes can secrete some specific organic activity acids to work but don’t destroy the living environment of plants such as soil. In contrast, this plants containing the pqq genes grew well, even better than other plants with lower phosphorus solubilization, in the phosphorus free medium even though its pqq genes activity and turned out phosphorus ring, while pqq dependent expression was induced.[Results]This reaserch that five pqq genes were cloned from Bacillus mycoides Gnyt1, phylogenetic analysis revealed that pBI-pqqA, pBI-pqqB, pBI-pqqC and pBI-pqqE similarly cluster with Phosphorus-soluble protein. Under the action of five promoters, each coding region of pqqA, pqqB, pqqC and pqqE from Bacillus mycoides Gnyt1 can directly participate in the phosphate solubilization of the strain, directly improving the phosphate solubilizing capacity of the plant, which have strong nitrogenase activity. Interestingly, changes in the phosphate solubilizing gene result in complete loss of the phosphate solubilization of the strain. However, the ability to dissolve the phosphorus ring and to dissolve the phosphorus was also exhibited in the medium having five phosphorus-dissolving genes.[Conclusions]The results indicated that the pqq genes were successfully cloned and a new specific phosphate-dissolving strain was formed. In this research, pqq genes were first cloned from Bacillus mycoides Gnyt1.

Screening and isolation of arsenic tolerant Rhizobacteria from arsenic contaminated areas of Bangladesh

An experiment was carried out to collect and isolate arsenic (As) tolerant rhizobacteria from As contaminated areas of Faridpur district. A total of 32 root samples of 17 plant species were collected from six locations of Bhanga and Nagarkanda upazila. From the plant roots, 16 rhizobacterial isolates were separated and their pure cultures were prepared. The collected rhizobacterial isolates were then characterized for morphological and biochemical traits. Among the bacterial isolates four were gram negative and 12 were gram positive. About 12 bacterial isolates had catalase producing capacity and the remaining three were negative to catalase test. Four bacterial isolates gave the positive HCN test. These bacterial isolates were grown on Pikovskays media to determine their phosphorus (P) solubilizing capacity. Four bacterial isolates had P solubilizing capacity and their Phosphorus Solubilizing Index (PSI) ranged between 3.00 and 4.66. However, isolate FB4 gave the highest P solubilization (4.66 PSI). For the evaluation of As tolerance, nutrient agar medium was prepared with different concentrations of As ranging from 30 to 600 ppm and the bacterial isolates were allowed to grow on the As contaminated medium for 36 hours. Isolate FB9 and FB4 showed maximum tolerance against As upto 600 ppm. Hence, these two isolates, both collected from Bhanga upazila and from wild brinjal species (Solanum capsicoides). Further research is needed to assess their effect on As dynamics at the rhizosphere, selection of suitable plant species for bacterial association and their potentials for field applications. Progressive Agriculture, Vol. 30, Suppl. 1: 17-25, 2019

IMPACT OF LIPASE ON MICELLE FORMATION AND SOLUBILIZATION ABILITIES OF NON-IONIC SURFACTANTS

Biotechnology is one of the fastest growing sector of scientific and applied activities of the humans, which needs to be successfully integrated into existing technologies. Such upcoming trend is the combination of conventional pulp treatment by surfactants and enzymatic processing in order to prevent pitch troubles in the pulp and paper mills. This article presents the research results of the abilities of non-ionic surfactants (sintamid-5, sintanol DS-10), enzyme (lipase) and their syner-gistic combinations to the micelle formation and solubilization. We chose the optimal synergistic compositions and investigated their colloid-chemical characteristics. There is no effect to the micelle formation ability of surfactants when addition of lipase is up to 30%. The largest deviation from the additive values of surface activity was observed for the mixture of individual non-ionic surfactant and lipase at the ratio of 70:30. However, in the all mixtures of both surfactants and lipase the ratio of experimental surface activity to the theoretically calculated is less than one. It looks, that hydrophilic areas of mixed aggregates block hydrophobic areas of lipase thereby preventing adsorption of lipase at the interface. A predominance of the surfactant in the composition will reduce its cost. The maximum of solubilizing capacity has sintanol DS-10 due to its highest HLB and the lowest CMC that leads to more micelles amount in solution and higher total hydrocarbon volume. The pitch solubilization in lipase solutions does not depend on enzyme concentration. The high pitch dissolving in synergistic mixture of sintanol DS-10 and lipase is observed. It is predetermines the usage of such systems for cellulose deresination.For citation:Smith R.A., Demyantseva E.Yu. Andranovich, O.S. Impact of lipase on micelle formation and solubilization abilities of non-ionic surfactants. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 6. P. 54-60

Enhanced stability and water solubilizing capacity of water-in-oil microemulsions based on protic ionic liquids

In view of this limited research on pILs in microemulsions, here we study the formation and characterization of a series of pIL–water/oil microemulsions with specific questions on the effect of pILs on water uptake capacity and thermal stability of W/O microemulsions.