Cow Manure Composting by Microbial Treatment for Using as Potting Material: An Overview

Preparation of high-temperature and low-temperature-resistant solid microbial agent for cattle manure fermentation and effect on composting

We used microbiology and molecular biology techniques to screen out high-temperature and low-temperature-resistant saprobiotics for compost and prepared a compound fermentation bacteria agent to rapidly ferment cattle manure into high-quality organic fertilizer in low-temperature season. Conventional composting and high-throughput techniques were used to analyze the changes of physical and chemical indexes and biodiversity in the process of composting, from which high and low-temperature-resistant strains were obtained, and high-temperature and low-temperature-resistant solid composite bactericides were prepared and added to composting to verify the effects of composite bactericides on composting. The conventional composting cycle took 22 days, and the diversity of microflora increased first and then decreased. Composting temperature and microbial population were the key factors for the success or failure of composting. Two strains of high-temperature-resistant bacteria and six strains of low-temperature-resistant bacteria were screened out, and they were efficient in degrading starch, cellulose, and protein. The high-temperature and low-temperature-resistant solid bacterial agent was successfully prepared with adjuvant. The preparation could make the compost temperature rise quickly at low temperature, the high temperature lasted for a long time, the water content, C/N, and organic matter fell quickly, the contents of total phosphorus and total potassium were increased, and the seed germination index was significantly improved. Improve the composting effect. The solid composite bacterial agent can shorten the composting time at low temperature and improve the composting efficiency and quality.

Effect of simplified inoculum agent on performance and microbiome during cow manure-composting at industrial-scale

A simplified inoculum agent, only comprising Bacillus subtilis and Aspergillus niger, was utilized for industrial-scale cow-manure composting to investigate its impact on composting performance and microbiome. Inoculants elevated the average and peak temperatures by up to 7 and 10 °C, respectively, during the thermophilic stage, reduced organic matter content, and raised germination index. Inoculation also extended the period of composting above 50 °C from 12 to 26 days. Sequencing unveiled significant shifts in microbial diversity, composition, and function. Aspergillus thrived during the mesophilic phase, potentially initiating composting, whereas Bacillus, Lysinibacillus, and Clostridium were enriched during the thermophilic stage. Metagenomic sequencing revealed an increased abundance of carbohydrate-active enzymes and glycometabolism-related genes responsible for lignocellulose degradation and heat generation after inoculation. These enriched microbes and functional genes contributed to organic matter degradation and temperature maintenance during thermophilic stage, expediting composting. This suggests the effectiveness of this simplified inoculum in industrial-level cow-manure composting.