THE POTENTIAL OF KONJAC FLOUR WASTE FOR LACTIC ACID PRODUCTION THROUGH BACTERIAL FERMENTATION Donna Jasmine Yoelinda1, Latifaturrohmah1, Sudarma Dita Wijayanti1 and Aji Sutrisno2*
1Department of food science and Biotechnology, Faculty of Agricultural Technology, Universitas Brawijaya, Malang, Indonesia
2Porang Research Center, Universitas Brawijaya, Malang, Indonesia
*Email: aji_sutrisno[at]ub.ac.id
Abstract
Konjac flour production generates solid waste, known as tobiko. In the production of konjac flour, 50-60% is converted into konjac flour and the remaining 40-50% produced as waste. Despite being classified as waste, tobiko is rich in carbohydrates, glucomannan, and other organic components, which make tobiko a highly potential substrate for microbial fermentation, particularly lactic acid fermentation. The rising demand for lactic acid in the past few years-driven by its application for biodegradable and eco-friendly products-has led to the improvements in lactic acid production to achieve high yields and quality of lactic acid. This study analyzed the potential of tobiko hydrolysate as a carbon source for lactic acid production using two lactic acid bacteria strains, L. lactis and L. plantarum. The fermentation conditions were carried out in 200 mL of tobiko hydrolysate with 5% (v/v) culture bacteria at 37 celcius, 125 rpm for four days. Growth kinetics, investigated via optical density at 600 nm, showed rapid growth within the first 24 hours, followed by a stationary phase. The pH decreased constantly throughout fermentation, indicating an increase in acid content. L. lactis achieved total acid yields of 1.26% - 2.83%, while L. plantarum produced 1.35% - 2.92%. These findings show that tobiko hydrolysate is a promising substrate for lactic acid bacteria metabolism and lactic acid production. Utilizing agroindustrial waste not only addresses environmental issues, but also supports the principles of a green economy and a circular economy. Future research needs to focus on optimizing the hydrolysis and scaling up the fermentation process.
