Biogas Production and Microbial Communities of Mesophilic and Thermophilic Anaerobic Co-Digestion of Animal Manures and Food Wastes in Costa Rica

Abstract

Biomass generated from agricultural operations in Costa Rica represents an untapped renewable resource for bioenergy generation. This study investigated the effects of two temperatures and three mixture ratios of manures and food wastes on biogas production and microbial community structure. Increasing the amount of fruit and restaurant wastes in the feed mixture significantly enhanced the productivity of the systems (16% increase in the mesophilic systems and 41% in the thermophilic). The methane content of biogas was also favored at higher temperatures. Beta diversity analysis, based on high-throughput sequencing of 16S rRNA gene, showed that microbial communities of the thermophilic digestions were more similar to each other than the mesophilic digestions. Species richness of the thermophilic digestions was significantly greater than the corresponding mesophilic digestions (F = 40.08, p = 0.003). The mesophilic digesters were dominated by Firmicutes and Bacteroidetes while in thermophilic digesters, the phyla Firmicutes and Chloroflexi accounted for up to 90% of all sequences. Methanosarcina represented the key methanogen and was more abundant in thermophilic digestions. These results demonstrate that increasing digestion temperature and adding food wastes can alleviate the negative impact of low C:N ratios on anaerobic digestion.

Multivariate comparison of taxonomic, chemical and technical data from 80 full-scale an-aerobic digester-related systems

“…Previous studies have also identified members of the orders Methanosarcinales , Methanobacteriales and Methanomicrobiales as the dominating methanogenic archaea in AD systems (Campanaro et al, 2016; Schnürer, 2016) Moreover, Methanosarcinales occurs in the core microbiome and can be detected in averages up to 5% (Murillo-Roos et al, 2022). According to the results, the MBA03 genera and Caldicoprobacter from the Bacillota phylum, the genus Proteiniphilum from Bacteroidota phylum, and an uncultured organism from Dethiobacteraceae family, compose the core microbiome of anaerobic digesters, as they are present in 100% of the processed samples with an abundance higher than 0.1% (Figure 3D).…”

Factores de interacción microbio-sustrato y gas-microbio en relación con la digestión anaeróbica del estiércol líquido y la productividad del cultivo

“…At a particular retention time, gas yield skyrockets with increasing temperature, which is opposite the trends shown by N and K. A high N (at 25℃) implies that the activity of microorganism or their conversion of the LM substrate to biogas is low. Because temperature increases reaction rate, a low N (at 45℃) by indication, shows that around the mesophilic temperature (Gaby et al, 2017;Murillo-Roos et al, 2022;Zeeman, 1991), the environment is most favorable for microorganisms to proliferate and generate more gases. Since both N and K has identical decreasing trends with temperature, high K is illustrative of the fact that gas production is limited due to either low microbial presence, insufficient nutrient or a near psychrophilic temperature regime which is not quite favorable in this experiment.…”

Valorization of Food Waste as Animal Feed: A Step towards Sustainable Food Waste Management and Circular Bioeconomy

“…Food that is excreted and digested ends up as organic waste, energy recovery, or landfill disposal. Reduction of food loss and waste is a serious challenge in India, which needs to feed its rapidly growing population (1.7 billion by 2050) [ 9 ]. In order to alleviate the environmental burden that is caused by FW, alternative methods are required to repurpose FW into uses with a higher value [ 10 , 11 ].…”