Production of lactic and acetic acids by Bacillus sp. ZM20 and Bacillus cereus following exposure to zinc oxide: A possible mechanism for Zn solubilization

Impact of Coating of Urea with Bacillus-Augmented Zinc Oxide on Wheat Grown under Salinity Stress

“…The separate application of Bacillus sp. AZ6 coated on urea may acidify the environment through producing organic acids and chelating Zn as previously reported by Hussain et al [ 25 , 26 ] and Mumtaz et al [ 29 ]. This treatment might also cause improvement in the uptake and translocation of Zn from the roots, shoots, and grains [ 54 ].…”

“…While ZnO is a cheaper source and contains 80% Zn, this concentration is insoluble in salt-affected and calcareous soils [ 28 ]. It is well-reported that Zn-solubilizing bacteria (ZSB) strains in soil have the power to solubilize insoluble Zn, and such available Zn could be termed as bioactivated Zn [ 25 , 26 , 29 , 30 , 31 ]. Hussain et al [ 25 , 26 ] reported that bioaugmented ZnO promoted the Zn use efficiency as compared to conventional ZnO and ZnSO 4 fertilizers.…”

“…Previously, several researchers reported an increase in the availability of Zn through the application of Bacillus spp. strains as potential bioinoculants [ 29 , 30 , 31 , 36 , 37 ]; however, the current study is novel regarding the formulation of a bioaugmented ZnO-coated urea product and its role in the alleviation of salt stress. Such bacterial strains have the power to solubilize the ZnO through producing volatile and non-volatile organic acids including acetic, caffeic, chlorogenic, cinnamic, citric, ferulic, formic, gallic, isobutyric, isovaleric, lactic, succinic, and syringic acids [ 30 , 36 ].…”

“…Pre-isolated and pre-characterized Bacillus sp. strain AZ6 (accession number KT221633) [ 23 ] having the ability to convert ZnO into an exchangeable form (Zn 2+ ) [ 29 ], was obtained from the Environmental Science Laboratory, Institute of Soil and Environmental Sciences (ISES), University of Agriculture Faisalabad (UAF), Pakistan. The strain AZ6 was grown in tris-minimal salt broth supplemented with 0.1% ZnO and incubated at 28 ± 1 °C for 48 h in a shaking incubator [ 24 ].…”

Production and Implication of Bio-Activated Organic Fertilizer Enriched with Zinc-Solubilizing Bacteria to Boost up Maize (Zea mays L.) Production and Biofortification under Two Cropping Seasons

“…As this strain has already been reported to solubilize Zn, it might have solubilized the insoluble source of Zn in soil resulting in the increased soluble fraction of Zn, subsequently improving grain and shoot Zn contents of maize. Such an increase in Zn contents in the rhizosphere has also been documented in response to the inoculation with some other potential Zn solubilizing microflora [32,48,68]. Whiting et al [69] stated that bioinoculant application improved water-extractable soil Zn from 51 to 74 mg kg −1 soil.…”