Acidification is a key technical problem in the dry anaerobic digestion system. The effect of bioaugmentation of butyric-resistant microorganisms (BRM) on an unstable acidified anaerobic digestion (AD) system was studied in this work. BRM were enriched in an AD system fed with butyric acid for 36 days. The slurry containing BRM was collected from the fermenter peak on the 24th day when methane production reached the peak, and transferred to an acidified fermenter fed with food waste. After the bioaugmentation, the acidified system was restored obviously. The concentration of butyrate decreased from 16.57 g/L to 5.06 g/L in the acidified system and the methane production increased by 52.2 mL/g-VS in the bioaugmentation treatment, compared to the fermenter without bioaugmentation. Syntrophomonas (Firmicutes) and Proteiniphilum (Bacteroidetes) were enriched in BRM, which contributed to maintain the interspecies electron transfer relationship with Methanosaeta. Therefore, bioaugmentation of BRM restored the integrity of microorganisms in AD and relieved pressure of VFA accumulation. This study provided an experimental and theoretical foundation for the management of acidification in dry AD of food waste.

The present study aimed to investigate the effect of serum derived from advanced platelet-rich fibrin on the healing of experimentally-induced corneal ulceration in donkeys. Nine adult apparently healthy donkeys of both sexes were used after being proofed normal after ophthalmological examination. A 6-mm-diameter centric corneal ulceration was induced chemically by using 1N sodium hydroxide solution. The donkeys were then randomly allocated into two main groups; control group (A), in which the corneal ulcer left for the period of the study without application of medicaments, and group (B), in which serum derived from advanced platelet-rich fibrin (s-PRF-drops) was applied to the eye three times/day for 35 days. Evaluation criteria included; clinical and external ophthalmic examinations, fluorescein staining, ulcer healing by analyzing serial digital photographs and histopathology. Results revealed no significant changes in the evaluation criteria between treatment and control groups. Corneal ulcer healing was associated with corneal opacity, vascularization, melanosis, and other complications that likely negate any potential benefit of administration of s-PRF as a treatment for corneal ulcer in donkeys. Histological results of the s-PRF-drops group were similar to the other group in the degree of re-epithelialization and regularity of the collagen bundles, type and maturity of the collagen. However, treatment by s-PRF drops resulted in no epithelial keratinization and slightly less sub-epithelial stromal inflammatory reaction.