Composting processes for food processing wastes: A review

Composting of food processing waste was analyzed as a biological process and an engineered system. The goal is to establish fundamental principles and design criteria that would aid its adoption as waste management practice. Characteristics of the inflow, reactor, and outflow were evaluated. Success of the bioreactor was found to be largely dependent on microbial community structure, physical properties of biodegradable waste (BW), aeration, heat transfer, and time required for maturation. Static piles were the primary focus of this article for cost and energy efficiency.

Amylase-Producing Fungi and Bacteria Associated with Some Food Processing Wastes

Amylases are enzymes that catalyze the hydrolysis of glycosidic bonds present in starch to release simple sugars. They are one of the most important enzymes in numerous commercial processes. In this investigation, fungal and bacterial strains from the following agro-industrial wastes were isolated and screened for amylolytic ability: soil from oil palm plantation, shea seed, date fruit, coconut meat, cassava effluent, cassava peel, cassava tubers, yam and potato tubers, starch medium, parboiled water from noodles and rice. The results revealed the presence of Geotrichum, Aspergillus, Penicillium, Trichoderma, Rhizopus and Fusarium spp. Five major genera of bacterial species namely Corynebacterium, Pseudomonas, Lactobacillus, Micrococcus and Bacillus were isolated and screened for amylase activity. Cassava soil had the highest heterotrophic bacterial count of 5.7 x105cfu/g and coconut meat waste had the lowest heterotrophic bacterial count of 1.3 x105cfu/g. All isolated microorganisms had the amylolytic ability. The fungal isolates had higher amylase activity when compared with the bacterial isolates. This investigation reveals organisms with high amylase activity.

Combined Use of Solar and Biomass Energy for Sustainable and Cost-Effective Low-Temperature Drying of Food Processing Residues on Industrial-Scale

In this study, a low-temperature drying plant based on renewable energies to dry food processing wastes is investigated. The demand-oriented heat supply is realized by a solar wall in combination with a biomass boiler. Due to the operational complexity of such a system with different sub-units and process parameters, steady-state simulations were performed in Aspen Plus to provide an insight into the process. Moreover, a time-resolved energetic evaluation was conducted to analyze the influence of varying capacity of the heat sources and operational strategy in addition to economic calculations. The simulations showed that an overall control strategy needs to consider the air properties as well as the flow rate of wet input material. In the reference case, the boiler must be operated at full load through the year to supply as much heat as possible. The revenue from the dried material was the most crucial parameter on the drying economics. Although the current plant configuration operating at 12 h per day and five days per week enable feasible results, the drying process can be more profitable by doubling the boiler capacity and increasing operational hours to 24 h per day and five days per week. The proposed plant can provide an environmentally friendly and cost-effective solution for the re-valorization of food-processing wastes into added-value compounds.