Role of microbial enzymes in the bioremediation of pollutants: a review

Abstract

A large number of enzymes from bacteria, fungi, and plants have been reported to be involved in the biodegradation of toxic organic pollutants. Bioremediation is a cost effective and nature friendly biotechnology that is powered by microbial enzymes. The research activity in this area would contribute towards developing advanced bioprocess technology to reduce the toxicity of the pollutants and also to obtain novel useful substances. The information on the mechanisms of bioremediation-related enzymes such as oxido-reductases and hydrolases have been extensively studied. This review attempts to provide descriptive information on the enzymes from various microorganisms involved in the biodegradation of wide range of pollutants, applications, and suggestions required to overcome the limitations of their efficient use.

Figure 1

The process of waste bioremediation.

Figure 2

Degradation of aromatic compound by monooxygenase [8].

Figure 3

Degradation of aromatic compound by dioxygenase [17, 18].

Figure 4

General reaction mechanism for phenol oxidation by laccase [21].

Figure 5

Lignin peroxidase (LiP)-catalyzed oxidation of nonphenolic β-O-4 lignin model compound [27].

Figure 6

Proposed mechanism for the oxidation of 2,6-dimethoxyphenol by the MnP system [28].

Figure 7

Proposed mechanism for triolein hydrolysis by Candida rugosa lipase in biphasic oil-water system. C_E represents the enzyme concentration in the bulk of the water phase [36].

Figure 8

Proposed mechanism for the hydrolysis of cellulose by the fungal cellulase enzyme system [39].

Figure 9

Proposed pathway for protease hydrolysis [45].