Optimization of acetate production from citrus wastewater fermentation

Citrus wastewater is a sugar-rich waste stream suitable for the recovery of energy of material from its treatment. In this study, fermentation of citrus wastewater was carried out to assess the optimal conditions to maximize the bioconversion of the organic substrate into acetate. Unbalanced nutrient (C: N: P 200:0.1:0.1) enabled the highest acetate production. The presence of the particulate organic fraction enabled to obtain a higher acetate concentration regardless the initial COD concentration. Initial pH values higher than 5 did not cause substantial differences on the maximum bioconversion of COD into acetate, whereas pH lower than 5 hindered the hydrolysis process. Lastly, the bioconversion rate of the organic substrate into acetate decreased from a maximum of 23% to a minimum of 8% related to the initial COD. The achieved results demonstrated that the characteristics of citrus wastewater enable its valorisation without the need to apply energy-consuming processes.

Automated summary

Citrus wastewater, rich in sugars, can be effectively fermented for energy recovery and material conversion. The study found that unbalanced nutrient ratios and the presence of particulate organic fractions can maximize acetate production. pH levels above 5 have minimal impact on bioconversion, while levels below 5 hinder the hydrolysis process. The results demonstrate the potential for valorisation of citrus wastewater without the need for energy-intensive processes.