Transformation of water states and succession of functional microorganisms during synergistic bioevaporation process

Abstract

A synergistic bioevaporation process was applied to treat the food waste (FW) by using the biofilm-developed corncob as the bulking agent and microbial carrier. During the process, interstitial water was the main water states, accounting for 55.6–76.8% of the total water amount. After the bioevaporation, 3079.27 g (61.05%) of the interstitial water and 48.46 g (3.45%) of the vicinal water was removed from the matrix, while 93.82 g (79.36%) of the bound water was formed. The removal of interstitial water mainly occurred in the cooling stage and the warming stage only lowered the binding energy of bound water, vicinal water and interstitial water. At the end of 1st cycle, the remained interstitial water trapped more tightly and the boundary between vicinal water and interstitial water nearly disappeared. The biofilm thickness in corncob particles was 350–440 µm and mainly dominated by bacteria and fungi with an abundance above 98.0%, in which the fungal Aspergillus reached as high as 22.7%. It seemed the fungi tended to survive in vicinal water abundant environment, but the bacteria preferred to habitat in interstitial water rich condition. Microorganisms had abundant metabolism genes of 29.3–38.5%, and the lipid transport and metabolic genes reached the maximum at Peak 54 ℃, while the carbohydrate transport and metabolic genes was the highest at Warming 46 ℃.