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International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
ISSN: 1735-1472 EISSN: 1735-1472
Vol. 13, No. 2, 2016, pp. 529-542
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Bioline Code: st16048
Full paper language: English
Document type: Research Article
Document available free of charge
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International Journal of Environment Science and Technology, Vol. 13, No. 2, 2016, pp. 529-542
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Biodegradation of phenol by a novel diatom BD1IITG-kinetics and biochemical studies
Das, B.; Mandal, T.K. & Patra, S.
Abstract
A phenol-degrading novel diatom BD1IITG
was isolated from petroleum refinery wastewater and
characterized (GenBank Accession No. KJOO2533).
HPLC analysis showed the diatom could degrade phenol in
the concentration range of 50–250 mg/l in Fog’s media.
The highest specific growth and degradation rate were
achieved at 100 mg/l phenol. It could also mineralize
phenol along with aliphatics in petroleum refinery
wastewater. Growth kinetic modeling shows that Haldane
model best represents the growth behavior of the diatom in
nutrient media as well as refinery wastewater. Biokinetic
parameters suggest that the diatom possesses higher maximum
specific growth rate (μmax = 0.4 day-1), better tolerance
to toxicity (KI = 90.24 mg/l) and high phenol
affinity (Ks = 20.99 mg/l) in refinery wastewater as compared
to Fog’s media confirming practical applicability of
the strain for wastewater treatment. FTIR fingerprinting of
biomass indicates intercellular phenol uptake and breakdown
into its intermediates via phenol degradation
pathway. Pathway was elucidated using HPLC, LC–MS
and UV–visible spectrophotometry confirming prominence
of ortho- over meta pathway for phenol metabolism. The
diatom produces biosurfactant with highest emulsifying
activity at 100 mg/l phenol which may contribute to
highest degradation rate at this concentration. Infrared
analysis confirms increased biosynthesis of lipids and
polysaccharides in phenol-degrading biomass, indicating
its potential use as feedstock of clean ecofriendly energy
sources as biodiesel or bioethanol. The phenol degradation
capability coupled with potential applicability of the spent
biomass as biofuel feedstock makes diatom BD1IITG a
potential candidate for a clean environmentally sustainable
process.
Keywords
Phenol; Diatom; Biodegradation; Growth kinetics; Pathway; Biosurfactant; Biofuel
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