In vitro nickel removal using nickel resistant bacteria isolated from an industrial wastewater treatment plant in Pasig City

Abstract

The contamination of the environment by heavy metals is a growing concern worldwide because of the extensive damage they cause to the health of the ecosystems and more so to human health. The use of microorganisms such as bacteria is a cheaper alternative to more expensive technologies in removing heavy metals in the environment. This study was able to isolate 16 nickel-resistant bacteria from a wastewater treatment facility of a glass factory in Metro Manila. The following putative isolates were identified through cultural, morphological, and biochemical characteristics determined using VITEK 2 Compact System. These were: Chryseobacterium indologenes, Acinetobacter haemolyticus, Acinetobacter lwoffi, Pseudomonas putida, Pseudomonas aeruginosa, Pseudomonas stutzeri, Pantoea sp., Enterobacter cloacae, Ochrobactrum anthropi, Alcaligenes faecalis. The minimum inhibitory concentration (MIC) of each isolate was measured, and the species with the greatest nickel tolerance was subjected to a growth and nickel biosorption study. All the isolates were able to grow in Tryptic Soy Broth (TSB) with a range of 130 ppm to 530 ppm nickel supplementation. Among the putative isolates identified, A. haemolyticus was able to tolerate and grow at 530 ppm nickel, whereas P. stutzeri and E. cloacae complex were able to tolerate and grow at 490 ppm nickel. The amount of nickel absorbed by A. haemolyticus in TSB supplemented with 270 ppm was 2.23 ± 0.87 ppm in 4 days. The results show that A. haemolyticus was able to accumulate 9.69% of the nickel in the solution. It is recommended that A. haemolyticus be studied further for its potential in the bioremediation of nickel in contaminated areas.