Pyrosequencing Reveals Soil Enzyme Activities and Bacterial Communities Impacted by Graphene and Its Oxides

Abstract

Graphene (GN) and graphene oxides (GOs) are novel carbon nanomaterial; they have been attracting much attention because of their excellent properties and are widely applied in many areas, including energy, electronics, biomedicine, environmental science, etc. With industrial production and consumption of GN/GO, they will inevitably enter the soil and water environments. GN/GO may directly cause certain harm to microorganisms and lead to ecological and environmental risks. GOs are GN derivatives with abundant oxygen-containing functional groups in their graphitic backbone. The structure and chemistry of GN show obvious differences compared to those of GO, which lead to the different environmental behaviors. In this study, four different types of soil (S1-S4) were employed to investigate the effect of GN and GO on soil enzymatic activity, microbial population, and bacterial community through pyrosequencing of 16S rRNA gene amplicons. The results showed that soil enzyme activity (invertase, protease, catalase, and urease) and microbial population (bacteria, actinomycetes, and fungi) changed after GN/GO release into soils. Soil microbial community species are more rich, and the diversity also increases after GO/GN application. The phylum of Proteobacteria increased at 90 days after treatment (DAT) after GN/GO application. The phylum of Chloroflexi occurred after GN application at 90 DAT in S1 soil and reached 4.6%. Proteobacteria was the most abundant phylum in S2, S3, and S4 soils; it ranged from 43.6 to 71.4% in S2 soil, from 45.6 to 73.7% in S3 soil, and from 38.1 to 56.7% in S4 soil. The most abundant genera were Bacillus (37.5-47.0%) and Lactococcus (28.0-39.0%) in S1 soil, Lysobacter and Flavobacterium in S2 soil, Pedobacter in S3 soil, and Massilia in S4 soil. The effect of GN and GO on the soil microbial community is time-dependent, and there are no significant differences between the samples at 10 and 90 DAT.

Assessing the Impacts of Cu(OH)2 Nanopesticide and Ionic Copper on the Soil Enzyme Activity and Bacterial Community

“…Soil bacteria, reflecting the quality and health of soil, are sensitive to environmental stress induced by contaminants . Both the soil bacterial community and enzyme activity play a key role in biological soil processes, such as pollutant degradation, nutrient cycling, or crop production. , Activities of urease, invertase, catalase, and acid phosphatase were considered as an important health indicator in previous studies; , therefore, these enzymes were selected in this study. However, bioavailability was enhanced and significant reduction in urea hydrolysis was achieved when labile soil C and clay particles were reduced.…”

The combined effect of graphene oxide and elemental nano-sulfur on soil biological properties and lettuce plant biomass

“…had enhanced activity by the single soil application of GO (compared to the Control). We attributed this result to the reported positive role of GO in sulfur oxidation and mineralization, as it was referred ( Rong et al., 2017 ), and to the beneficial general effect of GO on distinct soil microbiota and their activity ( Rong et al., 2017 ). Nevertheless, GO-promoted ARS activity was again discordant to the previous study ( Hammerschmiedt et al., 2022 ) and the role of different illumination in the soil microbial community composition (as reported by ( Carvalho and Castillo, 2018 )) and their related enzyme activities could be considered.…”

“…Contrary to the effect of nano-S, GO amendment to soil helped to preserve values of DHA and NAG (as well as other enzymes – urease, β-glucosidase, phosphatase) comparable with the Control, which was in contrast with the referred detrimental effect of GO ( Chung et al., 2015 ), but close to the opposite reports of a beneficial effect of graphene-based nanomaterials on soil enzymatic activities ( Ren et al., 2015 ). The other study ( Rong et al., 2017 ) showed that the positive or negative effect of either graphene or GO on microbial enzymes was vastly dependent on the composition of the soil microbial community. Arylsulfatase activity was enhanced by the single soil application of GO (compared to the Control) Arylsulfatase, as the only one from determined enzymes.…”

The Effects of Graphene-Family Nanomaterials on Plant Growth: A Review

“…GFN treatment decreases the activity of some soil enzymes, such as xylosidase, 1,4-β-N-acetyl glucosaminidase, and phosphatase [ 73 ], while increasing the activity of others, such as invertase, protease, catalase, and urease [ 74 ]. Although in vitro experiments showed that GFN treatment had a toxic effect on the soil microbial community [ 75 ], another study found that GO/GN application to the soil increased the diversity of the microbial community [ 74 ]. Compared with the mimic aquatic environment, GFN was shown to be much more retained in soil [ 40 , 76 ].…”