Biotechnology Progress 1995 May-Jun;11(3):235-50
Biosorption of heavy metals.
Volesky B, Holan Z. Department of Chemical Engineering, McGill University, Montreal, Canada.
Only within the past decade has the potential of metal biosorption by biomass materials been well established. For economic reasons, of particular interest are abundant biomass types generated as a waste byproduct of large-scale industrial fermentations or certain metal-binding algae found in large quantities in the sea. These biomass types serve as a basis for newly developed metal biosorption processes foreseen particularly as a very competitive means for the detoxification of metal-bearing industrial effluents. The assessment of the metal-binding capacity of some new biosorbents is discussed. Lead and cadmium, for instance, have been effectively removed from very dilute solutions by the dried biomass of some ubiquitous species of brown marine algae such as Ascophyllum and Sargassum, which accumulate more than 30% of biomass dry weight in the metal. Mycelia of the industrial steroid-transforming fungi Rhizopus and Absidia are excellent biosorbents for lead, cadmium, copper, zinc, and uranium and also bind other heavy metals up to 25% of the biomass dry weight. Biosorption isotherm curves, derived from equilibrium batch sorption experiments, are used in the evaluation of metal uptake by different biosorbents. Further studies are focusing on the assessment of biosorbent performance in dynamic continuous-flow sorption systems. In the course of this work, new methodologies are being developed that are aimed at mathematical modeling of biosorption systems and their effective optimization. Elucidation of mechanisms active in metal biosorption is essential for successful exploitation of the phenomenon and for regeneration of biosorbent materials in multiple reuse cycles. The complex nature of biosorbent materials makes this task particularly challenging. Discussion focuses on the composition of marine algae polysaccharide structures, which seem instrumental in metal uptake and binding. The state of the art in the field of biosorption is reviewed in this article, with many references to recent reviews and key individual contributions.
Publication Types:
Review
Review, academic
PMID: 7619394, UI: 95344632

Biochem Mol Biol Int 1996 Jul;39(4):789-95
Development of a metallothionein based heavy metal biosorbent.
Pazirandeh M
Center for Biomolecular Science and Engineering, Naval Research Laboratory, Washington, DC 20375, USA.
The potential utility of a recombinant E. coli expressing the Neurospora crassa metallothionein gene (NCP) as a heavy metal biosorbent was investigated. It was shown that the NCP was capable of efficiently removing low levels of several metals (including cadmium, lead, and mercury) from solutions. The reusability of the NCP was demonstrated through 5 cycles of metal binding, stripping with dilute acid, and regeneration of the binding sites with out any adverse effect on the metal binding activity. The NCP was successfully encapsulated in alginate and acrylamide without any inhibitory effect on its metal uptake activity. Furthermore, the metal uptake activity of the NCP was shown to be metabolism independent and resistant to solvents and other compounds (eg. polyaromatic hydrocarbons) which are often present along with heavy metals in waste waters thereby creating the potential for non-viable, encapsulated cells to be used.
PMID: 8843348, UI: 97000206


Radiats Biol Radioecol 1996 May-Jun;36(3):427-33
[The effect of algisorb on the level of the accumulation of zirconium, ruthenium, iodine and cesium radioactive isotopes in the body of rats].
[Article in Russian]
Ivannikov AT, Altukhova GA, Parfenova IM, Popov BA
The sorption effect of Algisorbum has been studied in rats following single and multiple intragastric administration. Algisorbum doses of 250-2000 mg/kg decrease the absorption of 106Ru and 95Zr by 50%, that of 137Cs by 15% and have no effect on 131I absorption. Application of a complex of agents to protect the body from nuclear fission products is discussed.
PMID: 8704921, UI: 96313874


Lebensm Unters Forsch 1992 Nov;195(5):455-8
Application of polyuronides for removing heavy metals from vegetable oils. III. Application of alginic acid, pectic and pectinic acids for demetalization of hydrogenated sunflower oil.
Ivanov K, Popova M, Denev P, Kratchanov C
Hochschule fur Lebensmittelindustrie, Plovdiv, Bulgaria.
Laboratory experiments have been carried out for the removal of heavy metals from hydrogenated vegetable oils using hydrated polyuronides (degree of swelling from 4 to 12.8 ml/g) such as alginic acid, pectic and pectinic acids. The effect of the type of polyuronide, degree of esterification and oil treatment on the degree of demetalization has been studied. It has been shown that with increase in the degree of esterification of the polyuronide the efficiency of demetalization decreases. The second and third treatment of the hydrogenated oil with pectinic acid resulted in a high degree of heavy metal removal. The possibility of efficient demetalization of hydrogenated oils by treatment with water solutions of pectinic acids has also been demonstrated.

The alginates found in kelp/seaweeds have a soothing and cleansing effect on the digestive tract and are known to help prevent the absorption of toxic metals like mercury, cadmium, plutonium and cesium. (Tanaka Y, et al, Application of algal polysaccharides as in vivo binders of metal pollutant. Proc Seventh Int Seaweed Symp, 602-607, Wiley & Sons, 1972) Kelp is also therapeutic for heart disease, high cholesterol, and high blood pressure. (Kameda J, I Fukushima Igaku Zasshi, 11, 289,1961; Funayama S, et al, Planta Medica, 41, 29, 1981; Kosuge T, et al, Yakugaku Zasshi, 103(6), 683,1983)

Ocean Algae's Beneficiary Effects
Ocean Algae are rich in proteins, vitamins, and important trace elements, including iodine and selenium.
Alginate Binds to Heavy Metals, Which are Secreted From the Human Body
The carbohydrates making up the algae cell walls are called alginate.
Alginate has the unique and important ability of binding heavy metals and radioactive substances to its own molecules. As the alginate cannot be broken down by the bile or saliva and cannot be absorbed by the body, it is secreted from the body together with the heavy metals and radioactive substances.
Alginate binds to all heavy metals, including lead, copper, zinc, mercury, cadmium, cobalt, and radium. The binding process takes place whether the metals are radioactive or not.
This is particularly important for cadmium and mercury, as these metals are found at
dangerously high levels in air, water, and food pollution. As an example, any greens grown within 175 feet of high traffic roads may contain toxic levels of heavy metals.
Alginate Can Remove Heavy Metals absorbed from previous Exposures
Alginate can also remove isotopes that have previously been absorbed by the human body from air, water, or food pollution. In the event that radioactive strontium is released into the body, the substance will be rotated by the blood until it is deposited into the bone structure. Even small amounts of radioactive pollution will expose surrounding cells with radioactive emission. Hence radioactivity should be removed from the body.
A percentage of strontium molecules stored in the bone structure is constantly released and is traveling with the bloodstream. As the blood feeds the saliva, gallbladder and bile, part of the released strontium ends up in the large intestine. Most of the liquid in the large intestine is reabsorbed by the body, including the radioactive isotopes, which are redeposited into the bone structure. Alginate can break this process, as strontium isotopes are bound to the alginate molecules and released from the body.
In Summary
The best prevention against heavy metal and radioactive absorption is to consume alginate before or during the meals. This will ensure a heavy metal and radioactive absorption of almost 100 percent, as the alginate comes in contact with all molecules.
Heavy metals and radioactivity that have previously been absorbed by the body are leaching and approximately one percent finds its way to the digestive system, where heavy metal removal is a longer process. Alginate should be consumed over at least a 4-months period in order to remove heavy metals and radioactive absorption caused by previous exposure.

University of Goteborg, Sweden,
Goran Michanek, Marine Biologist
Translated by Joar Opheim