Isolation and Identification of Heavy Metal Resistant Bacteria Producing Enzymes from Industrial, Laboratory and Dumping Sites Wastes in Mombasa County

Abstract

Industrial, laboratory and dumping sites wastes are sources of heavy metal introducing health risks to humans. However, bacterial strains living in such environments have capacity for wider industrial applications, including, productions of enzymes for detergent industry. The focus of the study was to screen and isolate enzymes produced by heavy metal-resistant bacteria. Wastewaters were collected from industrial discharge points at Tudor creek (TD) and laboratory effluent (TUL) at Technical University of Mombasa.  Soil samples were collected from damping site in Kongowea 1 (KG1), Kongowea 2 (KG2), Tudor ground (TG) and Tudor district hospital (TH) in Mombasa County. Bacteria strains were isolated using nutrient agar media and further sub-cultured to obtain pure colonies. Pure strains were screened for production of protease and amylase using lytic activity. Heavy metal tolerance test was used to screen for copper and mercury resistance to isolated bacteria. Microscopic and biochemical characteristics were used to identify bacteria with ability to grow in heavy metals and actively produce viable enzymes. Positive growth was realized in all sample collected from the six sites in varying concentration with copper plates recording the highest counts. Activity of microbial protease and amylase ranged from 0.1080±0.0025 in KG1 to 0.3703±0.0014 in TUL and 0.200±0.0745 in TUL 0.3613±0.0014 in TH respectively at a concentration of 2.5 mg/L of copper. At a concentration of 2.5 mg/L of mercury, activity of microbial protease and amylase ranged from 0.0113±0.0014 in TD to 0.2047±0.0014 in TH. There was no significant difference (p < 0.05) in microbial community and enzyme activity from the six sampling points. In all the sampling points, S. aureus, N. Veillonella, B. licheniformis, B. azotoformans, Streptococcus, Peptostreptococcus, Enterococcus and Acinetobacter/Moraxella were identified. The sites studied contained bacteria adapted to heavy metal pollution that can be natured to produce enzymes for situations demanding resistant enzymes such as detergent industries.