Sequential presence of heavy metal resistant fungal communities influenced by biochar amendment in the poultry manure composting process

Abstract

In this study, we investigated the influence of coconut shell biochar (CSB) on heavy metal resistance fungi (HMRF) during poultry manure (PM) composting by 18 S rDNA Internal Transcribed Spacer Amplicon Sequencing analysis. Five different concentrations of CSB (2.5%, 5%, 7.5%, and 10% dry weights basis) were applied with a mixture of PM and wheat straw (5:1 ratio dry weight basis) and without CSB (CK) was used as control. The results showed that sequence number rose along with increasing CSB concentration but total relative abundance (RA) of HMRF decreased 56.33%, 74.65% in T4 and T5, respectively. However, greater RA of HMRF was found in T1 or without biochar applied treatment. The phylum of Basidiomycota was the dominant fungal community accounting for 61.14%, 6.16%, 32.18%, 74.65%, and 73.73% from T1 to T5 of the total fungi abundance, with wide presence of the Wallemiomycetes and Eurotiomycetes classes. The Wallemia and Aspergillus were the richest genus and species. Wallemia_sebi , Altemaria_alternata and Aspergillus_amoenus were detected having greater abundance among all treatments. Besides this, the network correlation pattern confirmed that the relative greater percentage of correlation among dominant HMRF community with bio-available HM and other physicochemical factors increased with the addition of biochar. There was reasonable infer that the biochar amendment in composting could constitute favorable habitat for an active fungal population. • Biochar has positive effect to reduce heavy metal resistant fungal diversity by 56.33%–74.65%. • The superior fungi were Basidiomycota with relative abundance of 6.16–73.73%. • The 7.5% biochar can be efficiently altered the heavy metals resistant fungal diversity. • Coconut shell biochar remarkably effective to improve the poultry manure composting. • Biochar amendment in composting provided favorable habitat for an active fungal population.