A Review of the Current State and Future Prospects in Resource Recovery of Chinese Cereal Vinegar Residue

Abstract

Vinegar residue (VR) is a typical organic solid waste in Chinese cereal vinegar production. It is characterized by high yield, high moisture and low pH and is rich in lignocellulose and other organic matter. To avoid the environmental pollution caused by VR, it should be properly treated. The industry’s existing treatment processes, landfills and incineration, cause secondary pollution and waste of resources. Therefore, there is an urgent demand for environmentally friendly and cost-effective resource recovery technologies for VR. To date, a considerable amount of research has been performed in the area of resource recovery technologies for VR. This review summarizes the reported resource recovery technologies, mainly anaerobic digestion, feed production, fertilizer production, high-value product production and soil/water remediation. The principles, advantages and challenges of these technologies are highlighted. Finally, as a future perspective, a cascade and full utilization model for VR is proposed by considering the inherent drawbacks and economic-environmental feasibility of these technologies.

Optimising substrate conditions for microbial fermentation of vinegar residue

“…Similarly, it was observed that direct feeding of vinegar residue to pigs could lead to multiple problems such as constipation, discomfort, and indigestion (Jiang, 2008). However, fermenting vinegar residue with the aid of specific microbial strains was shown to effectively increase its nutrient content (Wang et al, 2022a). The present study indicated that the addition of 4.5% urea and 15% wheat bran to the fermenting mixture significantly increased the crude protein content compared to the control group.…”

“…Proper disposal of vinegar residue is crucial to prevent any adverse environmental impacts. Vinegar residue contains specific nutritional components, such as nitrogen-free extract, crude protein, and short-chain fatty acids, making it a potential feed ingredient (Wang et al, 2022a). However, the content of these components is insufficient to be fed directly to animals.…”

“…Microbial-transformed feed components, especially roughage fermentation, has become a significant trend in animal feed development. The process of fermentation acts as a pre-treatment for roughage, either with or without the use of microbial inoculants, to effectively decompose crude fibre, reduce its content and transform it into essential nutrients such as protein and sugar (Wang et al, 2022a). Additionally, microorganisms produce organic acids during fermentation, which can acidify feed, stimulate the secretion of digestive enzymes in the animal's gastrointestinal tracts, and facilitate gastrointestinal motility and digestion.…”