Insights into the Occurrence, Fate, Impacts, and Control of Food Additives in Food Waste Anaerobic Digestion: A Review

Abstract

The recovery of biomass energy from food waste through anaerobic digestion as an alternative to fossil energy is of great significance for the development of environmental sustainability and the circular economy. However, a substantial number of food additives (e.g., salt, allicin, capsaicin, allyl isothiocyanate, monosodium glutamate, and nonnutritive sweeteners) are present in food waste, and their interactions with anaerobic digestion might affect energy recovery, which is typically overlooked. This work describes the current understanding of the occurrence and fate of food additives in anaerobic digestion of food waste. The biotransformation pathways of food additives during anaerobic digestion are well discussed. In addition, important discoveries in the effects and underlying mechanisms of food additives on anaerobic digestion are reviewed. The results showed that most of the food additives had negative effects on anaerobic digestion by deactivating functional enzymes, thus inhibiting methane production. By reviewing the response of microbial communities to food additives, we can further improve our understanding of the impact of food additives on anaerobic digestion. Intriguingly, the possibility that food additives may promote the spread of antibiotic resistance genes, and thus threaten ecology and public health, is highlighted. Furthermore, strategies for mitigating the effects of food additives on anaerobic digestion are outlined in terms of optimal operation conditions, effectiveness, and reaction mechanisms, among which chemical methods have been widely used and are effective in promoting the degradation of food additives and increasing methane production. This review aims to advance our understanding of the fate and impact of food additives in anaerobic digestion and to spark novel research ideas for optimizing anaerobic digestion of organic solid waste.

Effects of Mixtures of Engineered Nanoparticles and Cocontaminants on Anaerobic Digestion

“…41 These bacteria have great potential for hydrolysis and may help provide a competitive advantage for methanogens to thrive in the digesters. 145 Currently, the complex influences of antibiotics and ENPs can be summarized in three key findings: (1) Coordination between antibiotics and ENPs to form complexes. 93 The concentration of metal ions released by the complex exceeds that released by individual ENPs under the same conditions.…”

Uncovering the Mechanisms of How Capsaicin Affects Short-Chain Fatty Acid Production during Food Waste Valorization

“…Rapid development in the food supply chain has led to an increased level of production of food waste (FW). More than 1.3 billion tons of FW are globally produced each year, and the annual amount is estimated to reach approximately 2.2 billion tons by 2025. , In China, the amount of FW reached 125 million metric tons in 2020 . As for the composition of FW, in addition to a large number of carbohydrates, lipids, and proteins, there are a lot of spices and condiments …”

“…For example, the daily consumption of capsaicin is 5 g/person in Thailand and 20 g/person in Mexico . This suggests that the accumulation of capsaicin in FW can reach up to 25 g/kg . Therefore, one must take into account the high levels of capacisin present when developing treatment and resource utilization plans for FW.…”

Single-cell metal–phenolic nanocoatings protect strictly anaerobic methanogens for methane production at an atmospheric oxygen level

“…Among known whole-microbe biocatalysts, methanogens are attractive catalysts that can directly reduce CO 2 to methane. 10,11 In addition, methanogens in anaerobic digesters enable the conversion of waste and wastewater into renewable methane, 12,13 a metabolic by-product that can be easily isolated, which can become part of the climate change solution as energy fuel and chemical precursors. 14,15 Methanogens can accept electrons directly from electrodes and increase methane production.…”