Statistical Assessment of Phenol Biodegradation by a Metal-Tolerant Binary Consortium of Indigenous Antarctic Bacteria

Kavilasni Subramaniam,Tengku Athirrah Tengku-Mazuki,Peter Convey,Azham Zulkharnain,Khalilah Abdul Khalil,Siti Aqlima Ahmad,Noor Azmi Shaharuddin,Claudio Gomez-Fuentes

doi:10.3390/d13120643

Abstract

Since the heroic age of Antarctic exploration, the continent has been pressurized by multiple anthropogenic activities, today including research and tourism, which have led to the emergence of phenol pollution. Natural attenuation rates are very slow in this region due to the harsh environmental conditions; hence, biodegradation of phenol using native bacterial strains is recognized as a sustainable remediation approach. The aim of this study was to analyze the effectiveness of phenol degradation by a binary consortium of Antarctic soil bacteria, Arthrobacter sp. strain AQ5-06, and Arthrobacter sp. strain AQ5-15. Phenol degradation by this co-culture was statistically optimized using response surface methodology (RSM) and tolerance of exposure to different heavy metals was investigated under optimized conditions. Analysis of variance of central composite design (CCD) identified temperature as the most significant factor that affects phenol degradation by this consortium, with the optimum temperature ranging from 12.50 to 13.75 °C. This co-culture was able to degrade up to 1.7 g/L of phenol within seven days and tolerated phenol concentration as high as 1.9 g/L. Investigation of heavy metal tolerance revealed phenol biodegradation by this co-culture was completed in the presence of arsenic (As), aluminum (Al), copper (Cu), zinc (Zn), lead (Pb), cobalt (Co), chromium (Cr), and nickel (Ni) at concentrations of 1.0 ppm, but was inhibited by cadmium (Cd), silver (Ag), and mercury (Hg).

Highlights

Antarctica and its surrounding Southern Ocean are widely considered to be among the Earth’s last pristine wildernesses, compared with the rest of the world, and has only recently been discovered and subsequently impacted by humans
Despite the strict guidelines provided in the Protocol on Environmental Protection to the Antarctic Treaty to protect the Antarctic environment, there remains potential for significant marine and terrestrial impacts at various scales due to accidents such as shipwrecks and pollution associated with research activities and research stations [2]
The present study focuses on the statistical evaluation of phenol degradation by a binary consortium of the Antarctic soil bacteria, Arthrobacter sp. strain AQ5-06, and Arthrobacter sp. strain AQ5-15 in combination with investigation of the consortium’s tolerance of exposure to different heavy metals

Summary

Introduction

Antarctica and its surrounding Southern Ocean are widely considered to be among the Earth’s last pristine wildernesses, compared with the rest of the world, and has only recently been discovered and subsequently impacted by humans. The continent has seen inexorable growth in scientific exploration, numbers, and extent of research stations, research activities, marine transportation and, more recently, tourism [1,2]. Human presence and activity present a distinct set of threats to the Antarctic environment, one of which is pollution [3,4]. Despite the strict guidelines provided in the Protocol on Environmental Protection to the Antarctic Treaty to protect the Antarctic environment, there remains potential for significant marine and terrestrial impacts at various scales due to accidents such as shipwrecks and pollution associated with research activities and research stations [2]. Historical and, in some cases, ongoing application of inappropriate waste management practices have led to the release of contaminants both to the surrounding terrestrial and near-shore aquatic environments [5,6,7]

Objectives

Methods

Results