Prokaryotic Diversity of the Composting Thermophilic Phase: The Case of Ground Coffee Compost

Abstract

Waste biomass coming from a local coffee company, which supplied burnt ground coffee after an incorrect roasting process, was employed as a starting material in the composting plant of the Experimental Station of the University of Naples Federico II at Castel Volturno (CE). The direct molecular characterization of compost using 13C-NMR spectra, which was acquired through cross-polarization magic-angle spinning, showed a hydrophobicity index of 2.7% and an alkyl/hydroxyalkyl index of 0.7%. Compost samples that were collected during the early “active thermophilic phase” (when the composting temperature was 63 °C) were analyzed for the prokaryotic community composition and activities. Two complementary approaches, i.e., genomic and predictive metabolic analysis of the 16S rRNA V3–V4 amplicon and culture-dependent analysis, were combined to identify the main microbial factors that characterized the composting process. The whole microbial community was dominated by Firmicutes. The predictive analysis of the metabolic functionality of the community highlighted the potential degradation of peptidoglycan and the ability of metal chelation, with both functions being extremely useful for the revitalization and fertilization of agricultural soils. Finally, three biotechnologically relevant Firmicutes members, i.e., Geobacillus thermodenitrificans subsp. calidus, Aeribacillus pallidus, and Ureibacillus terrenus (strains CAF1, CAF2, and CAF5, respectively) were isolated from the “active thermophilic phase” of the coffee composting. All strains were thermophiles growing at the optimal temperature of 60 °C. Our findings contribute to the current knowledge on thermophilic composting microbiology and valorize burnt ground coffee as waste material with biotechnological potentialities.

Combination Of Goat Rumen And Mas Snails As Decomposer Bacteria In Manufacturing Empty Palm Bunch Compost

“…The temperature of the compost decreased until on the 40th day the temperature was stable, namely 28º C and on the 41st day at level P2 the temperature reached the highest temperature, namely 52ºC. According to [19] that thermophilic microorganisms live at temperatures of 45-60°C and are tasked with consuming carbohydrates and proteins so that the compost material can be degraded quickly and the microorganisms found in the thermophilic phase are Actinomycetes and thermophilic fungi which are capable of breaking down cellulose and hemicellulose. An increase in the initial temperature at each research level indicates the presence of microorganism activity in the decomposition process.…”

Genome Sequence of the Thermophilic Soil Bacterium Ureibacillus terrenus ATCC BAA-384 T

“…U. terrenus is a rod-shaped, motile species displaying terminal or subterminal spherical endospores under appropriate conditions and is differentiated from the type species, Ureibacillus thermosphaericus , based on its isoprenoid quinone composition and ability to grow at higher temperatures (up to 65°C) and pH (up to 9.0) ( 2 , 3 , 5 , 7 ). U. terrenus and other members of its genus have been noted as important players in compost and waste decomposition ( 8 – 10 ) and have been investigated for biotechnology applications, given their thermophilic enzymes ( 11 – 16 ). Additionally, given recent emendations of the Ureibacillus genus within the family Caryophanaceae ( 17 , 18 ), the completion of the genome sequence for U. terrenus will contribute to further discussions of the taxonomic structure of this family.…”

Microbial community succession of cow manure and tobacco straw composting

“…Generally, composting occurs in three stages: mesophilic, thermophilic, and curing/mature phases (Papale et al, 2021). Throughout this process, aerobic microorganisms decompose organic waste into humus-like substances, enhancing soil quality as an amendment.…”