International Journal of Marine Science 2015, Vol.5, No.50: 1-5
1
Research Report Open Access
Effect of Heavy Metals (Pb, Cd, Cu) on the Growth of Sulphate Reduction
associated Bacterium
Clostridium bifermentans
Isolated from Cochin estuary,
Southwest coast of India
Binish M.B., Sruthy S., Mahesh Mohan
School of Environmental Sciences, Mahatma Gandhi University, Kerala, India
Corresponding author email
International Journal of Marine Science, 2015, Vol.5, No.50 doi
Received: 12 Jun., 2015
Accepted: 13 Jul., 2015
Published: 30 Aug., 2015
Copyright
©
2015 Binish et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article: Binish M.B., Sruthy S. and Mohan M., 2015, Effect of Heavy Metals (Pb, Cd, Cu) on the Growth of Sulphate Reduction
associated Bacterium
Clostridium bifermentans
Isolated from Cochin estuary, Southwest coast of India, International Journal of Marine Science, 5(50): 1-5
Abstract
Heavy metals like Lead (Pb), Cadmium (Cd) and Copper (Cu) causes serious environmental issues. The present study
investigated the tolerance and growth of
Clostridium bifermentans
isolated from Cochin estuary, southwest coast of India to three
different heavy metals such as Pb, Cd and Cu. Growth pattern of
Clostridium bifermentans
in different concentrations of selected
heavy metals were determined using spectrophotometer. Heavy metal tolerance (Cu, Cd, and Pb) were determined by minimal
inhibitory concentration (MIC). The strain exhibited multiple heavy metal resistances and showed markedly high tolerance to
cadmium and lead at minimum inhibitory concentration (MIC) of 12 µg/mL followed by copper (10 µg/mL). Presence of heavy
metals significantly affected the growth of
Clostridium bifermentans
. Presence of lead enhanced the growth of the strain while
cadmium and copper diminished the growth.
Keywords
Bioremediation; Pollution; Metal tolerance; Anaerobic
1 Introduction
The problem of pollution from heavy metals has
increased worldwide in the last 3 to 4 decades. Most
of the heavy metals are toxic and carcinogenic agents
which cause serious environmental issues and health
hazards to plants, animals and microorganisms. The
heavy metal mainly enters the environment through
various anthropogenic sources. Heavy metals have
great tendency to bio accumulate in the environment
and bio magnify in different trophic levels of food
web. Higher concentration of metals in environment
may kill majority of native microflora and some of
them would have evolved resistance mechanism over
heavy metals (Mohiuddin et al., 2011).
Higher concentration of heavy metals may exercise an
inhibitory action on microorganisms by blocking
essential functional groups, displacing essential metal
ions or altering the active confirmations of biological
molecules (Tejirian et al., 2010). Influence of heavy
metals in microorganism can also cause adverse effect
on its morphology, growth and biochemical activities
resulting decreased biomass and diversity (Barkay et
al., 1985). Therefore microbes may develop mechanism to
tolerate heavy metals either by efflux, complexation or
reduction of metal ions or use them as terminal
electron acceptors in anaerobic respiration (Gadd,
1990). The response of microorganism to heavy
metals may vary due to the concentration and
availability in polluted environment. As a result heavy
metal resistant bacteria can be used as biological
indicators of environmental contamination. Recent
studies have been reported that several microorganisms
had developed multiple resistances to heavy metals
(Singh et al, 2013, Jaysankar et al., 2008). It has
become obvious that chromosomal and plasmid borne
determinants for heavy metal resistance can transfer
freely within an ecological system such as soil (Top et
al., 1990).
Sulphate reducing bacteria (SRB) play a vital role in
heavy metal detoxification because they enzymatically
mediate the reduction of metals and forms less toxic
metal sulphides (De Luca et al., 2001., Aubert et al.,
1998., Macy et al., 2000). Sulphate reducing bacteria
have low metal tolerance capacity, so they depend on
some associated bacteria to cope with heavy metal
detoxification.
Clostridium
species are SRB associated
bacteria which plays a vital role in heavy metal
detoxification (Alexandrino et al., 2014).
Clostridium
