EMCB-ENVIS Node ENVIRONMENTAL BIOTECHNOLOGY

EMCB-ENVIS Centre
concentration levels of these heavy metals in normal soil. This situation indicates that there is
heavy metal pollution in the inspected area in E-5 Highway in Istanbul.
Nakajima Akira. (Department of Chemistry, Faculty of Medicine, Miyazaki Medical College,
Kiyotake, Miyazaki 889 16, Japan). Accumulation of gold by microorganisms . Journal
of Microbiology and Biotechnology, 19(4) (2003), 369-374.
Thirty species of microorganisms (8 bacteria, 9 actinomycetes, 8 fungi and 5 yeasts) were
screened for maximal gold accumulation. Extremely high abilities to accumulate gold from a
solution containing hydrogen tetrachloroaurate(III) were found in bacterial strains, such as
Escherichia coli and Pseudomonas maltophilia. Most of the actinomycetes, fungi and yeasts had
lower ability to accumulate gold than bacteria. Some microorganisms could accumulate similar
amounts of gold from a solution containing sodium gold(I) thiomalate as those from gold(III)
solution. However, most microorganisms tested accumulated far lesser amounts of gold from a
solution containing sodium dicyanoaurate(I) than from the other two gold solutions. The
accumulation of gold from the solution containing hydrogen tetrachloroaurate(III) by
Pseudomonas maltophilia was very rapid, was affected by the pH of the solution, and obeyed the
Langmuir adsorption isotherm. Pseudomonas maltophilia cells immobilized in polyacrylamide
gel adsorbed gold effectively from the solution containing hydrogen tetrachloroaurate(III). The
gold adsorbed on the cells was easily desorbed with 0.1 M thiourea solution. The immobilized
Pseudomonas cells could be used repeatedly in the adsorption–desorption cycle using 0.1 M
thiourea solution as desorbent.
O. S. Okay, P. Donkin, L. D Peters, D. R Livingstone. (TÜB TAK, MRC, Energy Systems and
Environmental Research Institute, PO Box 21, 41470, Gebze, Kocaeli, Turkey. CCMS,
Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3DH, UK. CCMS,
Plymouth Marine Laboratory, Citadel Hill, Plymouth PL1 2PB, UK). The role of algae
(Isochrysis galbana) enrichment on the bioaccumulation of benzo[a]pyrene and
its effects on the blue mussel Mytilus edulis. Environmental Pollution, 110(1) (2000),
103-113.
The role of algal concentration in the transfer of organic contaminants in a food chain has been
studied using the ubiquitous model polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) as
the contaminant, Isochrysis galbana as the phytoplankton food source, and the common mussel
(Mytilus edulis) as the primary consumer. The effect of algal concentration on BaP uptake by M.
edulis was determined by feeding M. edulis daily with I. galbana which had previously been
kept in the presence of BaP for 24 h. Four combinations of concentrations of algae and BaP were
used to give final exposure concentrations of 30,000 or 150,000 algal cells ml -1 in combination
with either 2 or 50 μg BaP l -1 . BaP concentrations were determined fluorometrically in rest
tissues (excluding digestive glands) and digestive gland microsomal fractions of M. edulis after
1, 7 and 15 days exposure, and also in isolated algae. Potentially toxic effects of BaP on M.
edulis were examined in terms of blood cell lysosomal membrane damage (neutral red dye
retention assay) and induction of digestive gland microsomal mixed-function oxygenase (MFO)
parameters [BaP hydroxylase (BPH) and NADPH-cytochrome c (P450) reductase activities].
BaP bioaccumulation in rest tissues (and to a lesser extent in digestive gland microsomes) of M.
edulis increased with both increasing BaP and algal exposure concentrations, and over time,
producing maximal bioconcentration factors in rest tissues after 15 days exposure to 150,000
algal cells ml -1 and 50 μg BaP l -1 of 250,000. The five-fold higher concentration of algae
increased BaP bioaccumulation by a factor of approximately 2 for 50 μg BaP l -1 at day 15. Blood
cell neutral red dye retention time decreased linearly with increasing log10 tissue BaP body
burden, indicating an increased biological impact on M. edulis with increasing BaP exposure
possibly due to a direct effect of BaP on blood cell lysosomal membrane integrity. An increase
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