PRODUCTION OF ORGANIC ACIDS FROM FERMENTATION OF KITCHEN WASTE

Abstract

Kitchen waste is any food substance, raw or cooked, which is discarded, or intended or required to be discarded, according to the legal definition of waste by the EU Commission.Food waste contains approximately 52.6% of moisture which is easily biodegradable and rich in nutrients and microflora (Hassan et al.,2001). Kitchen waste also could be anaerobically fermented to produce volatile fatty acids, aldehydes, alcohols and carbon dioxide (Stabnikovaet al.,2006).Hence, the objective of this study was to produce organic acids from kitchen waste. In this study, kitchen waste in ratio of 4:1:1 (rice:meat:vegetables) was fermented to produce organic acids, starting with inoculum preparation. Proximate analysis of kitchen waste was done to characterize the composition of kitchen waste. Fermentation was carried out in 500ml shake flask and incubated in shaker at 200 rpm. Ten per cent of fermented kitchen waste was used as inoculum source. Kitchen waste was fermented at three different pH which are pH 5, pH 6 and pH 7 at 37°C.The production of organic acids was analysed based on total sugar analysis, colony forming unit and organic acids analysis. Result obtained shows thatlactic acid was the predominant organic acids that produced with 6.246% concentration followed with acetic acid with 4.164% concentration and citric acid with 0.44% concentration. Results also revealed that pH 5 is the best pH to produce organic acids with the highest organic acids production (6.246%). Meanwhile, the highest colony count was in day six with 4.81 x 108cfu/ml and for total sugar analysis, sample with pH 5 shows the highest sugar consumption as the sugar concentration was decreasing rapidly. Hence, pH 5 and temperature of 37°C was the best conditions in order to produce organic acids from the fermentation process.