Brown sugar as a carbon source can make agricultural organic waste compost enter the secondary thermophilic stage and promote compost decomposition

Abstract

Abstract The utilization of microbial agents can enhance the composting process of agricultural organic waste and enhance the quality of compost products. However, several challenges persist in the composting of such waste, including the limited degradation capacity of the introduced microbial agents and the short duration of the high-temperature phase during composting. To enhance the composting efficiency of agro-organic waste, this study investigated the impact of inoculating tomato straw compost with two microbial agents: ZZ, a complex microbial agent, and EM, a commercial microbial agent. Additionally, 10% brown sugar was added as a carbon source to the compost after the initial high-temperature phase, aiming to assess its effect on the composting process. The findings revealed that compared to the control (CK) group, the ZZ and EM treatments extended the first high-temperature phase by 2 and 1 day, respectively. Furthermore, with the addition of 10% brown sugar, the ZZ and EM treatments remained in the second high-temperature phase for 8 and 7 days, respectively, while the CK treatment had already entered the cooling stage by then. Notably, the inoculation of microbial agents and the addition of brown sugar substantially augmented the activity of lignocellulose-related hydrolases, thereby promoting the degradation of lignocellulose in the ZZ and EM treatment groups. This was confirmed by FTIR analysis, which demonstrated that the addition of microbial agents facilitated the degradation of specific substances, leading to reduced absorbance in the corresponding spectra. XRD analysis further indicated a notable reduction in cellulose crystallinity for both the ZZ (8.00%) and EM (7.73%) treatments. Hence, the incorporation of microbial agents and brown sugar in tomato straw compost effectively enhances the composting process and improves the quality of compost products.