Succession of bacterial community during composting:dissimilarity between compost mixture and biochar additive

Previous research showed that biochar addition facilitated composting and elevated nutrient retention.However,few of these studies explored bacterial structure and abundance in the compost mixture and biochar additive.Thus,this study aims to distinguish bacterial communities in both compost and bamboo biochar(BB)additive.Results indicated that the dynamics of nutrient contents in compost and BB samples were in a similar pattern,although there were lower levels of nutrients and metals(i.e.,Cu and Zn)in BB additives.The total number of operational taxonomic units(OTUs)in both compost and BB additives peaked on day 7 and then gradually reduced during composting.There was more abundance of bacteria in compost,whereas the diversity of bacteria was more in BB additives.Furthermore,the dominant bacteria in compost and BB samples were distinct at the different stages of composting.The Firmicutes steadily decreased in compost samples(from 34.78%to 7.65%),while it was the dominant phylum in BB additives during the whole composting period.Furthermore,Ruminofilibacter,Pseudoxanthomonas,and Actinomadura were the most abundant genera in compost samples than Pseudoxanthomonas,Azoarcus,and Paenibacillus in BB additives at the final stage of composting.Results from this study could provide a theoretical reference for the sound performance of biochar-added composting.

High-throughput sequencing to evaluate the effects of methamphetamine on the succession of the bacterial community to estimate the postmortem interval

In forensic medical examinations,estimating the postmortem interval(PMI)is an important factor.Methamphetamine(MA)is a synthetic stimulant that is commonly abused,and estimation of the PMI after MA abuse has become one of the main tasks in forensic investigation.Microorganisms play a vital role in carrion decomposition.Analysing the bacterial succession patterns can be used as a forensic tool to estimate the PMI.The present study aimed to analyse bacterial succession changes during the decomposition of MA to estimate the PMI.We analysed bacterial communities in rabbits treated with three different concentrations of MA(0,22.5,and 90 mg/kg)under the natural conditions of 20°C and 70%humidity by sequencing 16S rRNA gene amplicons using the Illumina MiSeq system.We obtained 2374209 high-quality sequences and 2937 operational taxonomic units(OTUs).The relative abundances of the bacterial communities varied markedly in response to different MA concentrations.Interestingly,in response to the different concentrations of MA,Bacteroidetes became disparate in the rectum in the late PMI.Increased numbers of bacterial taxa were identified in the rectum and buccal cavity samples,except at the highest concentration of MA in the rectum samples when PMI was 0-h,than were present in live rabbits.Meanwhile,the PMI correlated significantly with bacterial succession at different taxonomic levels.Our results suggested that bacterial community succession could be used as a“microbial clock”to estimate the PMI in cases of MA-related death;however,further study is required to gain a deeper understanding of this concept.