Humic substances (HSs) are key indicators of compost maturity and are important for the composting process. The application of additives is generally considered to be an efficient and easy-to-master strategy to promote the humification of composting and quickly caught the interest of researchers. This review summarizes the recent literature on humification promotion by additives in the composting process. Firstly, the organic, inorganic, biological, and compound additives are introduced emphatically, and the effects and mechanisms of various additives on composting humification are systematically discussed. Inorganic, organic, biological, and compound additives can promote 5.58-82.19%, 30.61-50.92%, 2.3-40%, and 28.09-104.51% of humification during composting, respectively. Subsequently, the advantages and disadvantages of various additives in promoting composting humification are discussed and indicated that compound additives are the most promising method in promoting composting humification. Finally, future research on humification promotion is also proposed such as long-term stability, environmental impact, and economic feasibility of additive in the large-scale application of composting. It is aiming to provide a reference for future research and the application of additives in composting.Copyright © 2023 Elsevier Ltd. All rights reserved.

Effects of the heavy metal copper (Cu), the metalloid arsenic (As), and the antibiotic oxytetracycline (OTC) on bacterial community structure and diversity during cow and pig manure composting were investigated.&nbsp; Eight treatments were applied, four to each manure type, namely cow manure with: (1) no additives (control), (2) addition of heavy metal and metalloid, (3) addition of OTC and (4) addition of OTC with heavy metal and metalloid; and pig manure with: (5) no additives (control), (6) addition of heavy metal and metalloid, (7) addition of OTC and (8) addition of OTC with heavy metal and metalloid.&nbsp; After 35 days of composting, according to the alpha diversity indices, the combination treatment (OTC with heavy metal and metalloid) in pig manure was less harmful to microbial diversity than the control or heavy metal and metalloid treatments.&nbsp; In cow manure, the treatment with heavy metal and metalloid was the most harmful to the microbial community, followed by the combination and OTC treatments.&nbsp; The OTC and combination treatments had negative effects on the relative abundance of microbes in cow manure composts.&nbsp; The dominant phyla in both manure composts included Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria.&nbsp; The microbial diversity relative abundance transformation was dependent on the composting time.&nbsp; Redundancy analysis (RDA) revealed that environmental parameters had the most influence on the bacterial communities.&nbsp; In conclusion, the composting process is the most sustainable technology for reducing heavy metal and metalloid impacts and antibiotic contamination in cow and pig manure.&nbsp; The physicochemical property variations in the manures had a significant effect on the microbial community during the composting process.&nbsp; This study provides an improved understanding of bacterial community composition and its changes during the composting process.&nbsp; <br>

<p><List> <ListItem><ItemContent><p>&#8226; Manure utilization is hindered by separate specialist crop and livestock production systems.</p></ItemContent></ListItem> <ListItem><ItemContent><p>&#8226; Improving manure utilization requires organizations for manure exchange.</p></ItemContent></ListItem> <ListItem><ItemContent><p>&#8226; Policies and action plans for improving manure utilization are critically reviewed.</p></ItemContent></ListItem> <ListItem><ItemContent><p>&#8226; A manure chain approach with third-party contractors is recommended.</p></ItemContent></ListItem></List></p> <fig><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2095-7505-8-1-45/fase-20369-ws-tu1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2095-7505-8-1-45/FASE-20369-WS-tu1.tif"/></fig> <p>Livestock numbers in China have more than tripled between 1980 and 2017. The increase in the number of intensive livestock production systems has created the challenges of decoupled crop and livestock systems, low utilization of manures in croplands, and subsequent environmental pollution. Correspondingly, the government has enacted a series of policies and regulations to increase the sustainability of livestock production. This paper reviews the objectives of these policies and regulations and their impacts on manure management. Since 2017 there have been two policy guides to speed up the appropriate use of manures, three action plans for increasing manure recycling, and one technical guide to calculate nutrient balances. Requirements of manure pollution control and recycling for improved environmental performance of livestock production systems were included in three revised environmental laws. Most recent survey data indicate that the utilization of livestock manures was 70% in 2017, including that used as fertilizer and/or for production of energy. The targets for manure utilization are 75% in 2020 and 90% in 2035. To achieve these targets and promote &#8216;green livestock production&#8217;, additional changes are needed including the use of third-party enterprises that facilitate manure exchange between farms and a more integrated manure nutrient management approach.</p>

The objective was to determine the effects of psychrotrophic-thermophilic complex microbial agent (PTCMA) comprised of a psychrotrophic bacterium consortium (PBC) and a thermophilic cellulolytic fungi consortium (TCFC), on composting in a cold climate. Mixtures of dairy manure and rice straw were inoculated with PTCMA, PBC, TCFC and sterile water (control) and composted at an initial ambient temperatures of -2 to 5°C. In compost piles inoculated with PBC or PTCMA, temperatures reached the thermophilic phase (>55°C) faster (8-11d) than piles inoculated with TCFC or control. Furthermore, compost inoculated with TCFC or PTCMA had greater decreases in total organic carbon and carbon-to-nitrogen ratios, as well as significant increases in total nitrogen, degradation of cellulose and lignin and germination index than PBC inoculation or Control compost. Consequently, inoculation with both (i.e. PTCMA) accelerated the onset and promoted maturity of composting under cold-climate conditions.Copyright © 2017 Elsevier Ltd. All rights reserved.

In composting system, the composition of microbial communities is determined by the constant change in the physicochemical parameters. This study explored the dynamics of bacterial and fungal communities during cow manure and corn straw composting using high throughput sequencing technology. The relationships between physicochemical parameters and microbial community composition and abundance were also evaluated. The sequencing results revealed the major phyla included Proteobacteria, Bacteroidetes, Firmicutes, Chloroflexi and Actinobacteria, Ascomycota, and Basidiomycota. Linear discriminant analysis effect size (LEfSe) illustrated that Actinomycetales and Sordariomycetes were the indicators of bacteria and fungi in the maturation phase, respectively. Mantel test showed that NO-N, NH-N, TN, C/N, temperature and moisture content significantly influenced bacterial community composition while only TN and moisture content had a significant effect on fungal community structure. Structural equation model (SEM) indicated that TN, NH-N, NO-N and pH had a significant effect on fungal abundance while TN and temperature significantly affected bacterial abundance. Our finding increases the understanding of microbial community succession in cow manure and corn straw composting under natural conditions.

园林废弃物的日益增加给环境带来了巨大压力。微生物菌剂接种于园林废弃物中堆肥, 可以加速堆肥的腐熟度, 增强肥效, 改善并促进资源利用效率, 在园林废弃物再利用方面已显示较好的应用前景。从园林废弃物目前的处理方法和菌剂在堆肥化技术方面的应用着手, 介绍了微生物在园林废弃物堆腐中和发酵成微生物菌肥后的功能与作用, 阐述了目前监测堆肥腐熟程度的重要参数以及检测发酵过程中菌群变化的技术手段, 最后对微生物菌剂接种于园林废弃物堆肥化技术的前景进行了展望, 旨为相关领域的研究与开发提供参考和借鉴。

In this study, fresh cattle manure was mixed with rice straw at a ratio of 10:1 in fresh weight and then composted in a self-built, aerated static composting box, whose dimension was 1 m × 0.8 m × 0.8 m with a volume of approximately 0.6 m. To deal with the inconvenient and time-consuming problem of multiple stage inoculation, a single, one-time inoculation agent containing diverse microorganisms that are active at both the initial heating and thermophilic phases was developed. A total of 12 from 42 strains isolated from the none-inoculated Experiment 1 composting system were selected as microorganismal agents in Experiment 2 according to their species, prevalence and cultural temperature. 200 mL of each microorganism enrichment broth was mixed to the inoculation group at the beginning of composting. A total of 2400 mL of sterilize distilled water was added to the control group. The parameters of temperature, moisture, pH, C/N ratio, organic matter degradation, and germination index were investigated for both inoculation and control composting groups. Results showed that inoculation did not significantly shorten composting time. However, the pile temperature was increased with the maximum temperatures of 64.6 °C and 60.3 °C for the inoculation and control groups, respectively. The degradation of organic matter was accelerated (< 0.05), and significantly higher GI value (< 0.05) indicated that the maturity was promoted by the inoculation microorganism. This suggests that the final composting product would provide value as alternative source of nutrients for plants. Conclusively, we suggested a multiple microorganism inoculation method to increase the efficiency and promote maturity in cattle manure composting.© King Abdulaziz City for Science and Technology 2020.

Composting is an effective method of recycling organic solid waste, and it is the key process linking planting with recycling. To explore the reuse of agricultural organic solid waste as a resource in the Yellow River Delta, the effects of microbial inoculant and different additives (calcium superphosphate, biochar, tomato straw, rice husk, and sugar residue) on pile composting of cow dung were studied to obtain the best composting conditions. The results showed that microbial inoculant and additives all played positive roles in the process of aerobic composting, and the experimental groups outperformed the control groups without any additives. For discussion, the microbial inoculant promoted rapid pile body heating more than the recovery materials alone, and the effects on aerobic composting were related to the organic matter of substrates and biochar. After being composted, all the materials were satisfactorily decomposed. Degradation of additives into humic acid might serve as electron shuttles to promote thorough organic matter decomposition. These results provide a scientific basis data for industrial composting of organic solid waste processed by on-site stacking, and provide a reference for researcher and practitioners for studying the applications of microbial inoculant on aerobic composting.

The final products of shikimic acid pathway, aromatic amino acids (AAA), can be used as humic acid (HA) precursors. Therefore, the aim of this study was to explore the contribution of shikimic acid pathway on the formation of HA during composting. Four composting treatments were carried out in this study, including the control, biochar addition, montmorillonite addition, biochar and montmorillonite combined addition. The results showed that the correlations between AAA and HA were enhanced during combined addition composting, and functional microorganisms involved in the shikimic acid pathway increased. In addition, random forest model suggested that 63.3% of the top 30 genera contributing to the HA formation were functional microorganisms involved in the shikimic acid pathway, which fully proved the critical role of shikimic acid pathway. Therefore, this study provided a new perspective for revealing the crucial factors that promoted the formation of HA during composting.Copyright © 2021 Elsevier Ltd. All rights reserved.

Co-composting of raw manure with other organic sources has recently gained the attention of the scientific community. In the present study, raw manure and manures enriched with humic substances (Humac) or biochar were co-composted to improve their physico-chemical properties. We conducted an experiment including variants consisting of soil amended with manure (M), manure + Humac (M + H), manure + biochar (M + B), and unamended (control). Soil physico-chemical, biological, and plant properties were assessed altogether. All matured manures differed from each other physico-chemically (nutrient content) and in microbial composition, and hence their effects on the observed parameters. Compared to control, the soil respiration and enzyme activities related to N and P mineralization were enhanced due to the amendment of either manure or enriched manures. The M + H treatment resulted in higher pH of the manures as compared to other treatments, whereas the M + B and M treatments revealed the highest Corg contents of the final product, which was negatively correlated with HA:FA. In the same manner, M + H and M + B were the most prominent treatments, causing higher variations in basal soil respiration. The same treatments resulted in the highest percent increase values of soil enzymes related to C, N, and P, which further show the potential of manure modification as a viable option to boost soil fertility and health.

堆肥技术是有机固体废弃物处理处置与资源化利用最有效手段之一,涉及诸多复杂的非生物学与生物学反应。本文分别从非生物学及生物学层面阐述了腐殖化进程调控机制。非生物学腐殖酸合成机制涵盖了木质素-蛋白理论、多酚自缩合、多酚-蛋白途径以及美拉德反应。生物学途径包含堆肥进程碳组分的固定、木质纤维素的生物转化、反硝化进程等对腐殖化进程的响应。旨在为堆肥腐殖化进程中腐殖质的合成提供更为全面的技术参考和现状概述。

The capacity of microbes to degrade recalcitrant materials has been extensively explored for environmental remediation and industrial production. Significant achievements have been made with single strains, but focus is now going toward the use of microbial consortia owning to their functional stability and efficiency. However, assembly of simplified microbial consortia (SMC) from complex environmental communities is still far from trivial due to large diversity and the effect of biotic interactions. Here we propose a strategy, based on enrichment and dilution-to-extinction cultures, to construct SMC with reduced diversity for degradation of keratinous materials. Serial dilutions were performed on a keratinolytic microbial consortium pre-enriched from a soil sample, monitoring the dilution effect on community growth and enzymatic activities. An appropriate dilution regime (10) was selected to construct a SMC library from the enriched microbial consortium. Further sequencing analysis and keratinolytic activity assays demonstrated that obtained SMC displayed actual reduced microbial diversity, together with various taxonomic composition, and biodegradation capabilities. More importantly, several SMC possessed equivalent levels of keratinolytic efficiency compared to the initial consortium, showing that simplification can be achieved without loss of function and efficiency. This methodology is also applicable to other types of recalcitrant material degradation involving microbial consortia, thus considerably broadening its application scope.Copyright © 2020 Kang, Jacquiod, Herschend, Wei, Nesme and Sørensen.