Enhancing food waste biodegradation rate in a food waste biodigester with the synergistic action of hydrolase-producing Bacillus paralicheniformis GRA2 and Bacillus velezensis TAP5 co-culture inoculation

• Main Authors: Muhamad Aidilfitri Mohamad Roslan, Nur Qaiyyum Ummi Aiman Jefri, Nurhidayah Ramlee, Nor Aini Abdul Rahman, Nur Hazlin Hazrin Chong, Hamidun Bunawan, Izwan Bharudin, Mohd. Hafiz Abd. Kadir, Masita Mohammad, Halim Razali
• Format: Article
• Language: English
• Published: Elsevier 2021-05-01
• Series: Saudi Journal of Biological Sciences
• Subjects: Hydrolase-producing bacteria; Food waste biodigester; Bacillus spp.; Biodegradation
• Online Access: http://www.sciencedirect.com/science/article/pii/S1319562X21001133

Food waste (FW) minimization at the source by using food waste biodigester (FWBs) has a vast potential to lower down the impact of increasing organic fraction in municipal solid waste generation. To this end, this research sought to check the performance of locally isolated hydrolase-producing bacteria (HPB) to improve food waste biodegradation rate. Two under-explored HPB identified as Bacillus paralicheniformis GRA2 and Bacillus velezensis TAP5 were able to produce maximum amylase, cellulase, protease and lipase activities, and demonstrated a significant hydrolase synergy in co-culture fermentation. In vitro biodegradation analysis of both autoclaved and non-autoclaved FW revealed that the HPB inoculation was effective to degrade total solids (>62%), protein (>19%), total fat (>51), total sugar (>86%), reducing sugar (>38%) and starch (>50%) after 8-day incubation. All co-culture treatments were recorded superior to the respective monocultures and the uninoculated control. The results of FW biodegradation using batch-biodigester trial indicated that the 1500 mL and 1000 mL inoculum size of HPB inoculant reached a plateau on the 4th day, with gross biodegradation percentage (GBP) of >85% as compared to control (66.4%). The 1000 mL inoculum was sufficient to achieve the maximum GBP (>90%) of FW after an 8-day biodigestion in a FWB.