“PHYTOREMEDIATION OF PHENOLIC COMPOUNDS: RECENT ADVANCES AND PERSPECTIVES”

AGOSTINI, ELIZABETH; TALANO MELINA A,; GONZÁLEZ PAOLA S.; WEVAR OLLER ANA L.; MEDINA MARÍA I.

“Handbook of Phytoremediation”

Nova Science Publishers

Lugar: New York; Año: 2011; p. 1 - 50

Phenolic compounds present in the drainage from several industries are harmful pollutants and represent a potential danger to human health. Conventional treatments for phenol removal from industrial wastewaters have several limitations so, there is a need to look for alternative and environmental friendly technologies to complement or substitute the conventional ones. In recent years, phytoremediation has been recognized as a cheap and eco-friendly alternative technology which could be used for the remediation of organic contaminants, such as phenolics. Despite most phytoremediation studies were performed with soil-grown or hydroponically grown plants; more recently some results were obtained with the help of in vitro cell and tissue cultures, such as hairy roots. They have been used as tools for screening the potencialities of different plants species to tolerate, accumulate and remove high concentrations of phenols with high efficiency. In addition, using different plant model systems it could be established that plants metabolize a number of phenolic compounds by common metabolic pathways. Uptake of phenolics depends on the plant species as well as on their physicochemical properties. While the main metabolites detected from phenolic´s transformation are polar conjugates, some plant species could incorporate large amounts of these chemicals and associated metabolites, as bound residues, through reactions catalized by oxido-reductases. Hence, cell wall is considered one of the important detoxification sites of phenolic compounds in plants. In addition, plant roots produce and exude high amounts of oxido-reductive enzymes, such as peroxidases, which are associated with the non specific oxidative polymerisation of phenolic free radicals in the cell wall. So, these enzymes may play an important role in polymerising reactions and, also, they are likely to be the key enzymes in the removal of phenol and chlorophenols. Moreover, different peroxidase isoenzymes might play different roles in the removal process. So, in this chapter, the use of plants as enzyme sources, as well as the use of partially purified oxidases is discussed, as good alternatives for remediation purposes. On the other hand, with the use of genetic engineering, it is feasible to manipulate plant capacities to tolerate, accumulate, and/or metabolize pollutants, and thus to create an appropriate plant for environmental cleanup. Therefore, this chapter also examines and discusses the recent advances in enhancing phytoremediation of phenolic compounds through transgenic plant research.              Current knowledge, the areas which need to be explored and perspectives are presented to improve the efficiency and to asses the feasibility of phenolics´ phytoremediation.