Dynamic composting actuated by a Caldibacillus thermoamylovorans isolate enables biodecomposability and reusability of Cinnamomum camphora garden wastes

• DOI: 10.1016/j.biortech.2023.128852
• Publication Date: 2023-03-09T07:57:23Z
• Authors: Xiaowen Sun; Zhe Li; Jiaoqing Li; Zhi Li; Yini Ma; Zhicheng Zhou; Yongxuan Liu; Jie Zeng; Liangzheng Xu; Lin Li
• Keywords: Soil; Cinnamomum camphora; Composting; Bacillus; Gardens

The ecotoxic substances in Cinnamomum camphora garden wastes (CGW) often restrain microbe-driven composting process. Here, a dynamic CGW-Kitchen waste composting system actuated by a wild-type Caldibacillus thermoamylovorans isolate (MB12B) with distinctive CGW-decomposable and lignocellulose-degradative activities was reported. An initial inoculation of MB12B optimized for temperature promotion with reduced emission of CH4 and NH3 by 61.9% and 37.6%, respectively, increased germination index and humus content by 18.0% and 44.1%, respectively, and reduced moisture and electrical conductivity, and all were further reinforced by reinoculation of MB12B during the cooling stage of composting. High-throughput sequencing showed varied bacterial community structure and abundance following MB12B inoculation, with temperature-relative Caldibacillus, Bacillus, and Ureibacillus, and humus-forming Sphingobacterium emerging to dominate abundance, which strongly contrasted with Lactobacillus (acidogens related to CH4 emission). Finally, the ryegrass pot experiments showed significant growth-promoting effectiveness of the composted product that successfully demonstrated the decomposability and reuse of CGW.