Available phosphate content of an alluvial soil as influenced by inoculation of some isolated phosphate-solubilizing micro-organisms

Abstract

Summary Among several phosphate-solibilizing micro-organisms isolated from an alluvial soil (Fluvaquent) in sucrose-Ca3(PO,~) 2 agar plates, two fungal strains, ACF2 (Aspergillus eandidus) and ACF Z (A. fumigatus) two bacterial strains, ACB s (Baeillusfirmus B-7650) and ACB~ (B. firmus B-7651) and one actinomycete strain, ACSo (Streptomyces sp.) were efficient solubilizers, solubilizing 297.0, 288.3, 49.0, 45.8 and 29.0 p.g of P as free PO4 -3, respectively, containing 15 mg insoluble P from Ca3(PO4) 2 in broth. Solubilization was lesser from A1PO 4 and FePO 4. The isolates producing oxalic and tartaric acids without or with citric acid showed higher ability of solubilizing insoluble inorganic phosphates.All the above isolates possessed the ability of solubilizing rock phosphate in considerable amounts, ACF 1 (A.fumigatus) being the highest (31.5 p.g), while ACB 6 (B.firmus B-7651) and both the aspergilli also possessed cellulose-decomposing ability in addition. Inoculation of the isolates, in a flask culture experiment, had no significant effect on the accumulation of available phosphorus in soil even when amended with rock phosphate (RP), farm yard manure (FYM), (FYM + RP), rice straw (RS) and (RS + RP). Nevertheless, the overall performance ofACF 2 (A. candidus) and ACB 6 (B.firmus B-7651) was better than that of the others, in this respect, while ACB 5 (B. firmus B-7650) and ACF 1 (A. fumigatus) intensified the enhancing effect of FYM and RS. Partial sterilization, by autoclaving, of the soil had no significant effect on available phosphorus content of the soil irrespective of any inoculation.

Evaluation of Phosphate Solubilizing Potential of Three Burkholderia Species Isolated from Green House Soils

“…This observation in consistent with earlier reports, which have shown that the very low Al phosphate solubilization by Burkholderia cepacia DA23 (Song et al, 2008). This may be probably due to the adaptive nature of the enzyme that is responsible for solubilizing Ca 3 (PO 4 ) 2 (Banik and Dey, 1982). However, a few reports have indicated the other soil microorganisms to solubilize hardly soluble Fe or Al phosphates (Barroso et al, 2006;Antoun, 2002).…”

Solubilização de fostatos por microrganismos na presença de fontes de carbono

“…Além disso, existem diferenças na capacidade e no potencial de solubilização dos microrganismos. Determinado microrganismo pode solubilizar apenas Ca-P, enquanto outros ainda solubilizam Al-P e Fe-P, devendo-se levar em consideração que os microrganismos podem solubilizar esses fosfatos em diferentes intensidades (Banik & Dey, 1982;Doyle et al, 1990).…”

“…Na avaliação do efeito de fontes de carbono, foram utilizados 21 isolados selecionados de acordo com suas características morfofisiológicas (Silva Filho, 1998) Nenhum isolado produziu halo no meio com fosfato de ferro, apenas cinco produziram-no na presença de fosfato de alumínio e, com exceção do isolado 148, todos solubilizaram fosfato de cálcio. A baixa incidência de microrganismos solubilizadores de fosfatos de cálcio que solubilizam fosfatos de alumínio ou de ferro também tem sido encontrada por outros autores (Banik & Dey, 1982;Toro et al, 1996). Em alguns casos, os isolados solubilizam somente fosfatos de cálcio (Louw & Webley, 1959;Duff et al, 1963;Wenzel et al, 1994).…”

“…Isto concorda, em parte, com os trabalhos de Carvalho et al (1969), Banik & Dey (1982) e onde espécimes deste gênero são indicados como solubilizadores de fosfatos de alumínio. Vários outros gêneros (Pseudomonas, Penicillium, Erwinia, Enterobacter e Bacillus) têm sido apontados como solubilizadores de fosfatos de alumínio e, ou, de ferro (Duff et al, 1963;Carvalho et al, 1969;Banik & Dey, 1982;Toro et al, 1996). No entanto, os isolados indicados por Silva Filho (1998), como pertencentes a estes gêneros, não demonstraram tal atividade.…”

Isolation of Phosphate Solubilizing Microorganism (PSM) from Reclaimed Fly Ash Zone of Mejia Thermal Power Station (MTPS) and its Implications

“…Phosphate solubilization by PSB strain is associated with the release of low molecular weight organic acids, which causes their hydroxyl and carboxyl group to chelate the unwanted cations bound with phosphate converting it from insoluble form to soluble form [16][17][18]. The process is followed by the release of organic acids such as glycolic, oxalic, malonic and succinic acid into the surrounding media by the PGPR strains, most of which have been reported to have efficient phosphorus solubilizing ability [19]. In addition to this, PSB strains releases inorganic acids like sulphidric, carbonic and nitric acid, which further act as a chelating agent thus transferring P into soluble form for the easy utilization of crops [20 -23].…”