Modeling anaerobic digestion metabolic pathways for antibiotic-contaminated wastewater treatment
BIODEGRADATION
Authors: Fonseca, Rafael Frederico; de Oliveira, Guilherme Henrique Duarte; Zaiat, Marcelo
Abstract
Anaerobic digestion has been used to treat antibiotic-contaminated wastewaters. However, it is not always effective, since biodegradation is the main removal mechanism and depends on the compound chemical characteristics and on how microbial metabolic pathways are affected by the reactor operational conditions and hydrodynamic characteristics. The aim of this study was to develop a mathematical model to describe 16 metabolic pathways of an anaerobic process treating sulfamethazine-contaminated wastewater. Contois kinetics and a useful reaction volume term were used to represent the biomass concentration impact on bed porosity in a N continuously stirred tank modeling approach. Two sulfamethazine removal hypotheses were evaluated: an apparent enzymatic reaction and a cometabolic degradation. Additionally, long-term modeling was developed to describe how the operational conditions affected the performance of the process. The best degradation correlations were associated with the consumption of carbohydrates, proteins and it was inversely related to acetic acid production during acidogenesis.
Visible-light-induced dearomative oxamination of indole derivatives and dearomative amidation of phenol derivatives
CHEMICAL COMMUNICATIONS
Authors: Wu, Lingang; Hao, Yanan; Liu, Yuxiu; Song, Haibin; Wang, Qingmin
Abstract
Herein, we report a protocol for visible-light-induced dearomative oxamination reactions of indole derivatives to afford functionalized spirocyclic products. These step-economical reactions, which involve C-N and C-O bond formation, feature mild conditions, a broad substrate scope, high yields, exclusive diastereoselectivity and step-economy. In addition, a similar protocol could be used to synthesize spirolactams by dearomative amidation of phenol derivatives.