Volatile organic compounds and dominant bacterial community during aerobic composting of vegetable waste and cow manure co-complexing

Abstract

Vegetable waste was aerobically composed using a trough-type system, and the resulting emitted volatile organic compounds were investigated. In addition, the succession pattern of microorganisms was analyzed. Aerobic fermentation was conducted using a tomato stalk-cow dung mix (a water content of 65% and a carbon-to-nitrogen ratio of 25:1). The emitted volatile organic compounds comprised of 58 kinds of compounds, including 2 sulfur-containing compounds, 3 alcohols, 3 esters, 3 aldehydes, 3 ketones, 6 halogenated hydrocarbons, 18 aromatic hydrocarbons, 17 alkanes, and 3 alkenes. The primary volatile organic compounds produced were methyl sulfide, ethyl acetate, ethanol, and acetaldehyde. Clustering and principal coordinate analysis suggested that the community succession changed throughout the composting process in the odor-producing habitat. High-throughput sequencing revealed that the bacterial community was comprised of Firmicutes, Chloroflexi, Proteobacteria, and Actinobacteria, whereas the dominant flora included Ascomycota, Basidiomycota, and Mucoromycota. These findings could aid in the mitigation of volatile organic compounds and odors during vegetable waste composting as well as contribute to the development of deodorizing bacteria.