Statistical
optimisation for enhancement of phenol biodegradation by the Antarctic soil
bacterium Arthrobacter sp. strain AQ5-15 using response surface
methodology
K. Subramaniam1, N.A.
Shaharuddin1, T.A. Tengku-Mazuki1, A. Zulkharnain2,
K.A. Khalil3, P. Convey4 and S.A. Ahmad1,5*
1Department of
Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti
Putra Malaysia, 43400, Serdang, Selangor, Malaysia
2Department of
Bioscience and Engineering, College of Systems Engineering and Science,
Shibaura Institute of Technology, 307 Fukasaku, Minuma-ku, Saitama-337 8570,
Japan
3Department of
Biomolecular Sciences, Faculty of Applied Sciences, Universiti Teknologi
MARA, 40450, Shah Alam, Selangor, Malaysia
4British Antarctic
Survey, NERC, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom
5National Antarctic
Research Centre, B303 Level 3, Block B, IPS Building, Universiti Malaya,
50603, Kuala Lumpur, Malaysia
*Corresponding Author Email : aqlima@upm.edu.my
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Abstract
Aim:
Effective bioremediation requires optimisation of conditions under which the
process takes place. In this study, an Antarctic soil bacterium, Arthrobacter
sp. strain AQ5-15, was evaluated for phenol biodegradation under
statistically optimised conditions.
Methodology: The composition of degradation media and the culture
conditions for this study were determined according to the experimental
requirements obtained from Plackett-Burman factorial design (PB) and
Box-Wilson Central Composite Design (CCD), respectively. Phenol degradation
was monitored by 4-aminoantipyrine colorimetric assay and bacterial growth
was quantified by measuring optical density (OD600 nm)
at 72 hr.???? ??????????
Results:
A preliminary screening experiment using the Plackett-Burman design indicated
that all the factors screened (ammonium sulphate concentration, sodium
chloride concentration, pH and temperature) had significant influence on
degradation performance. Response Surface Methodology was then utilised to
further optimise the phenol-degrading process using Central Composite Design.
The maximum percentage of phenol degradation achieved with CCD was 99.42%,
under medium conditions of 0.15 g l-1 (NH4)2SO4,
0.13 g l-1 NaCl, pH 7.25 and incubation at 15?C for 72
hr. The strain could degrade phenol when exposed to an initial concentration
of up to 1.5 g l-1 under these optimised conditions.? ?????????????????
Interpretation: The tolerance and degradation
characteristics of strain AQ5-15 suggest that it has potential application in
bioremediation of polluted sites and in the treatment of relatively cool
water bodies contaminated with phenol.?? ?????
Key words: Arthrobacter sp., Aromatic hydrocarbon,
Bioremediation, Indigenous, Psychrotolerant
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