Edible biofilm formation from guava seed waste fermentation

Abstract

Guava seed is by-product from the consumption of guava fruits. We interested to explore further the potential of guava seed waste using fermentation method. The purpose of this research was to determine the ability of biofilm formation produced from fermentation of guava seed. Fermented guava seed was prepared by solid-state fermentation method using banana leaves wrap at 37 °C for 72 h. It were then continued with isolation and screening of bacteria from the fermentation products, preparation of bacteria cultures to be used in biofilm formation, and formation of biofilm by glass slides and broth cultures methods. The edible biofilm formation by glass slide method was observed by light microscopy using 0.5 % Crystal Violet dye, while biofilm formation by broth cultures method was observed by transmission electron microscopy (TEM) using phosphotungstic acid 2 % dye. The results show that there were 3 (three) strains lactic acid bacteria (LAB) candidates isolated from fermented guava seed waste product (J6, J7, and J8 strains). The observation by light microscopy showed that J7 strain was the only strain which was unable to form biofilm by glass slide method. All the strains showed the ability to form biofilms in different stages by broth cultures method. Thus, guava seed fermentation was able to produce edible biofilm but the LAB strains still need to be identified further.