Cyanobacteria As A Removal Agent Of Heavy Metal
By
Muhammad Afdal
GS 20787
The Assignment to fulfil the subject of
Beneficial Microbe in Agrobiotechnology
School of Graduate Study
Universiti Putra Malaysia
August 2008
1. Introduction
The use of Cyanobacteria in reducing the heavy metal waste in industrial area becomes trend nowadays as it could lessen the existing of the heavy metal in the waste. This waste becomes a major cause of environment due to the health effect related with them. Many researches have been done to reduce the existing of the heavy metal from wastewater by using Cyanobacteria (Anjana et al, 2007; El-Enany and Issa, 2000; and Cain et al, 2008). Some reports mentioned that cyanobacteria have been used as an absorbent agent in removing the heavy metal like Cadmium, Lead, Cromium (Anjana et al, 2007; El-Enany and Issa, 2000; and Cain et al, 2008). Therefore the aim of this paper is to show some information concerning the role of cyanobacteria as an agent of removing the heavy metal.
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Blue-green Algae (pdf)
These questions and answers provide information to address health concerns about exposure to blue-green algal toxins in surface waters (lakes, rivers, streams and reservoirs).
What are blue-green algae?
Blue-green algae, technically known as cyanobacteria, are microscopic organisms that are naturally present in lakes and streams. They usually are present in low numbers. Blue-green algae can become very abundant in warm, shallow, undisturbed surface water that receives a lot of sunlight. When this occurs, they can form blooms that discolor the water or produce floating rafts or scums on the surface of the water.
Environmental Toxicology and Pharmacology 8 (2000) 95–101
Cyanobacteria as a biosorbent of heavy metals in sewage water
A.E. El-Enany *, A.A. Issa
Botany Department, Faculty of Science, Assiut University, Assiut, Egypt Abstract (pdf)
The effect of sewage water on some physiological activities of cyanobacteria was studied. Metal-tolerant cyanobacterium (Nostoc linckia) and metal-sensitive (Nostoc ri6ularis) were grown at three levels of sewage water (25, 50 and 75%). The growth rate showed significant stimulation in low and moderate levels (50% for N. linckia and 25% for N. ri6ularis). Not only the number of cells was elevated but also, the time required to reach the exponential and the stationary phases was reduced. Also, low levels of sewage water increased chl.a content, photosynthetic O2-evolution, respiration and protein content. Similarly, heterocyst frequency as well as nitrogenase activity were increased in cyanobacteria grown at low and moderate levels (25 and 50% sewage). On the other hand, the high level of waste (75%) reduced growth and metabolic activities of the two species. N. linckia accumulated about 30-fold of Zn and ten-fold of Cd than those of growth medium (50% sewage water). Also, N. ri6ularis accumulated about ten-fold of Zn and two-fold of Cd. The distribution of Cd and Zn in cells were investigated. About 65–60% of Cd or Zn were found in pellets (sediment) as insoluble form in the two species. The soluble form (cytosolic fraction) after being fractionated on sephadex G-(75-100) revealed two peaks with molecular weights of 70–75 and 40–45 kDa. These peaks were in coincidence with Cd and Zn maxima. Nostoc ri6ulais showed more sensitivity to heavy metals than N. linckia, and accumulated less amount of metal-binding proteins. Nostoc linckia seems to be tolerant to heavy metals (Zn and Cd) and is able to accumulate
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