Influence of reduced graphene oxide on the growth, structure and decomposition activity of white-rot fungus Phanerochaete chrysosporium

Abstract

Graphene materials have attracted great interest nowadays due to their large-scale production and wide applications. It is urgent to evaluate the ecological and environmental risk of graphene materials for the healthy development of the graphene industry. Herein, we evaluated the influence of reduced graphene oxide (RGO) on the growth, structure and decomposition activity of white-rot fungus, whose decomposition function is vital for carbon cycle. RGO slightly stimulated the fresh weight and dry weight gains of Phanerochaete chrysosporium. A larger number of fibrous structures were observed at low RGO concentrations in P. chrysosporium, which was consistent with the elongation of cells observed under a transmission electron microscope. RGO did not affect the chemical composition of P. chrysosporium.Moreover, the laccase production of P. chrysosporium was not influenced by RGO. The degradation activities of P. chrysosporium for dye and wood appeared to be promoted slightly, but the differences were insignificant compared to the control. Therefore, RGO had low toxicity to white-rot fungus and was relatively safe for the carbon cycle.

Toxicological response of the model fungus Saccharomyces cerevisiae to different concentrations of commercial graphene nanoplatelets

“…The influence of graphene derivatives on the viability of other fungi has been little studied. Recently, two studies reported the impact of graphene oxide and reduced graphene oxide on the filamentous fungus Phanerochaete chrysosporium, with the latter compound showing lower toxicity for the fungus than the former 42,43 . Besides carbon nanomaterials, the toxicological impact on S. cerevisiae of various metal oxide nanoparticles have been evaluated as well, generally showing low toxicity [50][51][52] .…”

“…The viability of S. cerevisiae cells exposed to two GN concentrations (160 and 800 mg L −1 ) and exposure times (2 and 24 h) was assessed through colony forming units (CFU) determination. The concentrations selected to assess the biological impact of GN on yeast cells were based on previous concentration ranges used by other authors in recent studies, where the impact of distinct graphene derivatives on fungal species was studied [41][42][43][44] . Also, a previous study provided toxicology data at transcriptomics level by exposing S. cerevisiae to 160 mg L −1 45 , so we considered interesting to use the mentioned concentration to assess and compare the toxicological response…”

Toxicity of Pristine and Chemically Functionalized Fullerenes to White Rot Fungus Phanerochaete chrysosporium

“…Upon chemical reduction, RGO stimulated the fresh weight gain of P. chrysosporium at 0.25 mg/mL and higher. A meaningful dry weight stimulating effect was observed at RGO concentrations of 1.0 mg/mL and higher [ 31 ]. Huang et al reported that Fe 3 O 4 nanoparticles (NPs) slightly inhibited the biomass gain of P. chrysosporium at 0.5 mg/mL after 1 d exposure and stimulated the biomass gain at day 3 [ 36 ].…”

“…Xie et al reported that graphene oxide (GO) inhibits the growth of white rot fungi and leads to the complete loss of degradation activity for dye [ 27 ]. Yang et al suggested that chemical reduction alleviates GO effects on white rot fungi [ 31 ]. After reduction by vitamin C, reduced GO (RGO) does not suppress the degradation activity of white rot fungi.…”

“…Similarly, RGO hydrogels and xerogels were found to immobilize and enhance the Lac production of white rot fungus Trametes pubescens [ 32 ]. In addition, protein level studies have indicated that carbon nanotubes and graphene influence the enzyme activity of white rot fungi [ 31 , 33 ]. For fullerene, its impact on the decomposition of white rot fungi has not been evaluated yet, which hinders the full understanding of the environmental safety of fullerene.…”