Critical Review of Anaerobic Biodegradation of Benzenediols: Catechol, Resorcinol, and Hydroquinone

Abstract

Dihydroxybenzenes (DHBs) are widely used to manufacture a variety of chemicals. Because of their broad array of uses, they are found in the effluents of many industries and cause environmental contamination of aquifers and soils. Among various techniques for DHB removal, anaerobic biodegradation can achieve complete and cost-effective elimination of aromatic pollutants through diverse microbial metabolic processes. Successful application of microorganisms to biodegradation requires a deeper understanding of how microbial degradation proceeds under different environmental conditions in batch/continuous processes. In the degradation of a multicomponent feed, the initial acclimation of biomass to a specific component plays an important role in the subsequent biodegradation of the feed. Biodegradation of single and multiple components of DHBs in aqueous environments has not been adequately addressed. In the context of the available literature, the writers’ paper reviews the metabolic pathways of anaerobic degradability under methanogenic, denitrifying, sulfate-reducing, and fermentation conditions. In addition, the writers also critically review anaerobic degradation of DHBs in batch tests and in continuous reactors, such as upflow anaerobic fixed film-fixed bed reactors and upflow anaerobic sludge blanket reactors.