The quality of composts prepared in automatic composters from fruit waste generated by the production of beverages

Effect of different bulking agents on fed-batch composting and microbial community profile

The current study focused on analyzing the effect of different types of bulking agents and other factors on fed-batch composting and the structure of microbial communities. The results indicated that the introduction of bulking agents to fed-batch composting significantly improved composting efficiency as well as compost product quality. In particular, using green waste as a bulking agent, the compost products would achieve good performance in the following indicators: moisture (3.16%), weight loss rate (85.26%), and C/N ratio (13.98). The significant difference in moisture of compost products (p < 0.05) was observed in different sizes of bulking agent (green waste), which was because the voids in green waste significantly affected the capacity of the water to permeate. Meanwhile, controlling the size of green waste at 3-6 mm, the following indicators would show great performance from the compost products: moisture (3.12%), organic matter content (63.93%), and electrical conductivity (EC) (5.37 mS/cm). According to 16S rRNA sequencing, the relative abundance (RA) of thermophilic microbes increased as reactor temperature rose in fed-batch composting, among which Firmicutes, Proteobacteria, Basidiomycota, and Rasamsonia were involved in cellulose and lignocellulose degradation.

Humification and maturation of kitchen waste during indoor composting by individual households

This study evaluated the humification and maturation of kitchen waste during indoor composting by individual households. In total, 50 households were randomly selected to participate in this study using kitchen waste of their own for indoor composting using a standard 20 L sealed composter. Garden waste was also collected from their local communities and used as the bulking agent. Both effective microorganisms and lime were inoculated at 1% (wet weight) of raw composting materials to facilitate the composting initiation. Results from this study demonstrate for the first time that ordinary residents could correctly follow the instruction to operate indoor composting at household level to manage urban kitchen waste at source. Overall, 30 households provided valid and complete data to show an increase (to ~50 °C) and then decrease in temperature in response to the decline of biodegradable organic substances during indoor composting. The compost physiochemical characteristics varied significantly toward maturation with an increase in seed germination index to above 50% for most households. Furthermore, organic humification occurred continuously during indoor composting as indicated by the enhanced content of humic substances, degree of polymerization, and spectroscopic characteristics.

Novel Biodegradable Poly (Lactic Acid)/Wood Leachate Composites: Investigation of Antibacterial, Mechanical, Morphological, and Thermal Properties

This research aimed to investigate the effects of using wood leachate (WL) powder as a cost-effective filler added to novel poly (lactic acid) biocomposites and evaluate their mechanical, thermal, morphological, and antibacterial properties. Fourier transform infrared spectroscopy (FTIR), tensile test, Charpy impact test, Shore hardness, scanning electron microscope (SEM), differential scanning calorimetry (DSC), contact angle, and bacterial growth inhibition tests were employed to characterize the developed biocomposites. The SEM results indicated a proper filler dispersion in the polymer matrix. WL powder improved the hydrophobic nature in the adjusted sample’s contact angle experiment. Markedly, the results showed that the addition of WL filler improved the mechanical properties of the fabricated biocomposites. The thermal analysis determined the development in crystallization behavior and a decline in glass transition temperature (Tg) from 60.1 to 49.3 °C in 7% PLA-WL biocomposites. The PLA-WL biocomposites exhibited an antibacterial activity according to the inhibition zone for Escherichia coli bacteria. The developed novel PLA-WL composites can be effectively utilized in various value-added industrial applications as a sustainable and functional biopolymer material.