The use of sulfate-reducing bacteria (SRB) in passive treatments of acidic effluents containing heavy metals has become an attractive alternative biotechnology. Treatment efficiency may be linked with the effluent conditions (pH and metal concentration) and also to the amount and nature of the organic substrate. Variations on organic substrate and sulfate ratios clearly interfere with the biological removal of this ion by mixed cultures of SRB. This study aimed to cultivate a mixed culture of SRB using different lactate concentrations at pH 7.0 in the presence of Ni, Mn and Cu. The highest sulfate removal efficiency obtained was 98 %, at a COD/sulfate ratio of 2.0. The organic acid analyses indicated an acetate accumulation as a consequence of lactate degradation. Different concentrations of metals were added to the system at neutral pH conditions. Cell proliferation and sulfate consumption in the presence of nickel (4, 20 and 50 mg l(-1)), manganese (1.5, 10 and 25 mg l(-1)) and copper (1.5, 10 and 25 mg l(-1)) were measured. The presence of metals interfered in the sulfate biological removal however the concentration of sulfide produced was high enough to remove over 90 % of the metals in the environment. The molecular characterization of the bacterial consortium based on dsrB gene sequencing indicated the presence of Desulfovibrio desulfuricans, Desulfomonas pigra and Desulfobulbus sp. The results here presented indicate that this SRB culture may be employed for mine effluent bioremediation due to its potential for removing sulfate and metals, simultaneously.

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High yields obtained from soybean [Glycine max (L.) Merrill], and consequent profits, are related to efficient symbiosis of soybean with nitrogen fixing bacteria of the Bradyrhizobium genus. Inoculation with strains belonging to the Bradyrhizobium japonicum, B. elkanii, and B. diazofficiens species, approved by the Brazilian Ministry of Agriculture (MAPA), is a common practice for this crop. However, variations in the composition of inoculants can change the quality of the product. The aim of this study was to genetically identify and to evaluate the symbiotic efficiency of isolates with cultural characteristics different from those of strains approved by MAPA and which are present in two commercial inoculants for soybean. Isolates obtained from inoculants and the strains SEMIA 5079 (CPAC 15), SEMIA 5080 (CPAC 7), SEMIA 587 (BR 96), and SEMIA 5019 (BR 29), indicated in the formulation of these inoculants, were tested for symbiotic efficiency in soybeans (cultivar: COODETEC 5G 830 RR) in a greenhouse. Identification by partial sequencing of the 16S rRNA gene, together with BOX-PCR analysis, showed that variant isolates were not similar to the inoculant strains indicated in the commercial products, despite belonging to the same genus and/or species. No loss was observed in the nodulation ability of the isolates; however, significant differences were reported in the symbiotic efficiency of the isolates compared to the inoculant strains approved by MAPA. Nevertheless, the presence of morphological variants did not influence the efficiency of inoculant products.

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Data presented here are related to the original paper “Simultaneous removal of sulfate and arsenic using immobilized non-traditional sulfate reducing bacteria (SRB) mixed culture and alternative low-cost carbon sources” published by same authors (Matos et al., 2018) [1]. The data set here presented aims to facilitate this paper comprehension by giving readers some additional information. Data set includes a brief description of experimental conditions and the results obtained during both batch and semi-continuous reactors experiments. Data confirmed arsenic and sulfate were simultaneously removed under acidic pH by using a biological treatment based on the activity of a non-traditional sulfur reducing bacteria consortium. This microbial consortium was able to utilize glycerol, powdered chicken feathers as carbon donors, and proved to be resistant to arsenite up to 8.0 mg L−1. Data related to sulfate and arsenic removal efficiencies, residual arsenite and sulfate contents, pH and Eh measurements obtained under different experimental conditions were depicted in graphical format.Refers to https://doi.org/10.1016/j.cej.2017.11.035

Several microbiological indicators of soil quality present high sensitivity, but little is known about the influence of topographic factors on them. This work aimed to evaluate variability of biological indicators of soil quality across a hillslope under native forest and the influence of topographic factors on them. Four positions on a hillslope were evaluated. Activity of the enzymes β-glucosidase, acid phosphatase, urease and fluorescein diacetate (FDA) hydrolysis were determined, as well as basal and substrate-induced respiration, and density of microorganisms: total bacteria, total fungi, actinobacteria, phosphate solubilizers, ammonifiers, native rhizobia, free-living N 2 -fixing bacteria, spores of arbuscular mycorrhizal fungi and percentage of root colonization by arbuscular mycorrhizal fungi. Activity and density of microorganisms were correlated with topographic factors. The relation of these factors to the variations of the evaluated indicators was determined using the random forest algorithm. Microbiological indicators varied according to the hillslope positions. The indicators urease, basal respiration, spore density, mycorrhizal colonization, total bacteria and fungi, phosphate solubilizers, and free-living N 2fixing bacteria detected in JNFB and FAM culture medium did not vary with terrain attributes and were therefore more indicated in cases of topographic variations. This and future studies can help to select the best microbiological indicators for different conditions.

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