Potassium solubilization in phonolite rock by diazotrophic bacteria

Abstract

Some strains of nitrogen fixing bacteria, besides fixing the N 2 , can produce phytohormones, control pathogens, act in solubilization of minerals containing phosphorus (P) and potassium (K), contributing to plant growth. However, the solubilization of minerals containing K has been little exploited. Therefore, the aim of this study was to evaluate potassium solubilization (K) of phonolite rock by strains of associative nitrogen fixing bacteria supplied with two different carbon sources. Twelve bacterial strains were cultured for seven days at 25°C in Aleksandrov medium supplemented with phonolite rock powder. The experiment was carried out in a completely randomized factorial design, 13 x 2 (12 bacterial strains and a control without inoculation) and two carbon sources (glucose and sucrose) with four repetitions. After the growth, the supernatant was separated by centrifugation and analyzed for the final pH value and the content of K. All diazotrophic bacteria strains contributed to increase the release of K when compared to the control treatment. The strain UNIFENAS 100-94 solubilized 130 mg L -1 K in the presence of the two carbon sources, indicating the potential use of these diazotrophic bacterial strains for K solubilization from minerals.Keywords: bio-solubilization, carbon source, rock powder Solubilização de potássio da rocha fonolito por bactérias diazotróficas ResumoAlgumas estirpes de bactérias diazotróficas, além de fixar o N 2 , são capazes de produzir fitormônios, controlar patógenos e solubilizar minerais que contenham fósforo (P) e potássio (K), contribuindo para o crescimento vegetal. No entanto, a solubilização de minerais contendo K tem sido pouco explorada. Portanto, o objetivo deste estudo foi avaliar a solubilização de potássio (K) da rocha fonolito por estirpes de bactérias diazotróficas associativas supridas com duas fontes diferentes de carbono. Foram utilizadas 12 estirpes bacterianas cultivadas por sete dias a 25°C em meio líquido Aleksandrov suplementado com pó de rocha fonolito. O experimento foi instalado em delineamento inteiramente casualizado, em esquema fatorial 13 x 2 (12 estirpes bacterianas e um controle sem inoculação) e duas fontes de carbono (glicose e sacarose) com quatro repetições. Após o cultivo, o sobrenadante foi separado por centrifugação e analisado o valor do pH final e a concentração de K. A redução do pH foi diretamente relacionada à maior concentração de K. Todas as estirpes bacterianas diazotróficas contribuíram para maior liberação de K quando comparado ao tratamento controle, destacando-se a estirpe UNIFENAS 100-94, que solubilizou cerca de 130 mg L -1 de K na presença das duas fontes de carbono, indicando o potencial de utilização desta estirpe bacteriana diazotrófica e solubilizadora de minerais contendo K na agricultura.

Solubilization of Araxá natural phosphate and decomposition of plant residues by bacterial isolates

“…Strains UNIFENAS 100-13 and UNIFENAS 100-39 also have a proven ability to solubilize potassium and the efficiency of the process varied according to the carbon source (Florentino et al, 2017). In this study, it was possible to observe that the carbon source positively influences phosphorus solubilization, which is directly related to the lowering of the pH value, as shown in Figure 1.…”

<b>Symbiosis of rhizobia with <i>Gliricidia sepium </i> and <i>Clitoria fairchildiana</i> in an Oxisol in the pre-Amazon region of Maranhão State

“…Several authors have reported on the ability of gliricidia to establish symbiosis only with fastgrowing rhizobia, and it has been proposed that gliricidia preferentially achieves effective symbiosis with strains of this type (Turk & Keyser, 1992;Moreira, Gillis, Pot, Kersters, & Franco, 1993;Melchor-Marroquín, Vargas-Hernández, FerreraCerrato, & Krishnamurthy, 1999;Thiao, Neyra, Isidore, & Sylla, 2004;Florentino et al, 2014). However, the strains were not genetically identified in these studies.…”

“…This is not the case for the species studied here, whose seeds are not available during all seasons and also quickly lose viability. Although several studies have authenticated gliricidia strains in their original host (Florentino et al, 2014;Bala & Giller, 2006;Turk & Keyser, 1992;McIroy et al, 1999;MelchorMarroquim et al, 1999;Acosta-Durán & MartinezRomero, 2002;Thiao et al, 2004), no studies have been conducted to authenticate the strains in sombreiro, or to analyse the Nif and Nod genes in the strains in either species. Although siratro can be nodulated with every strain in the nodulating genera in the present study, the legume was nodulated with all the strains isolated from sombreiro nodules (belonging to the Bradyrhizobium genera), but it was not nodulated with some Rhizobium strains, nor with the Methylobacterium strain isolated from gliricidia, nor with the Mesorhizobium strain isolated from gliricidia.…”

Growth promotion of Guinea grass by diazotrophic bacteria1

“…These strains have been studied for their ability to fix N 2 in Brachiaria brizantha cv. Xaraés (Dias et al 2019), solubilize potassium (Florentino et al 2017b) and produce IAA (Florentino et al 2017a). A group of diazotrophic bacteria strains selected at the Universidade José do Rosário Vellano (Unifenas) was prioritized in this study.…”