Bacterial community changes during composting of municipal crop waste using low technology methods as revealed by 16S rRNA

Abstract

Bacterial communities are actively involved in composting process but the environment within the compost influences their diversity, abundance and succession. In this study, the authors investigated the bacterial communities in tropical crop waste compost using pyrosequencing. Municipal crop wastes from the tropics (Uganda) were composted under four different low-technology methods. Samples were collected from the early thermophilic, late thermophilic, and mesophilic phases, and from mature compost. Pyrosequencing of the amplified variable V4 region of the 16s rDNA generated over 110 000 sequences. Chao1 and cluster analysis at 3% dissimilarity showed that bacterial community richness declined during the composting process. The community was dominated by a few bacterial taxa during the thermophilic phases. Species evenness increased as compost progressed to maturity despite a decline in the number of taxa over the successional progression. Bacterial community diversity, abundance and succession changed with the composting method. This pattern of diversity may be attributed to competition and selection during the microbial succession. A total of 22 phyla and 513 genera were identified from all the methods in the entire composting process. The most abundant phyla were Proteobacteria, Firmicutes, Bacteriodes and Actinobacteria. Pyrosequencing provided more information on compost bacterial community diversity and abundance than previously used molecular methods. Several novel bacteria existing in tropical crop waste compost remained unclassified.

Microbial Community Succession and Response to Environmental Variables During Cow Manure and Corn Straw Composting

“…A significant relationship was found between NO 3 - -N and NH 4 + -N with the fungal abundance but not with bacteria abundance, suggesting that growth of fungi was more sensitive to changes of NO 3 - -N and NH 4 + -N than that of bacteria. This might be as a result of NH 4 + -N being the preferred nitrogen source for most microorganisms ( Geisseler et al, 2010 ) and the conversion of NH 4 + -N to NO 3 - -N (nitrification) is an important energy resource ( John and John, 2018 ). However, NO 3 - -N and NH 4 + -N significantly influenced the bacterial community composition but not fungal community, this indicates that succession of bacterial community was more sensitive to the variation of NO 3 - -N and NH 4 + -N than that of fungal community.…”

Effectiveness of Composter with Magic Compos System Forward Reverse Design Through Temperature and Humidity Control on Composing Quality

“…Household waste is waste consisting of the remains of foodstuffs, vegetables, fruit peels, used wrappers and food processing waste 1 . Household waste management needs to be carried out to reduce the generation of organic waste that can trigger diarrhea, skin and respiratory diseases 2 . With the support of science, composting methods are very important to be carried out by every individual or community group.…”