NISCAIR Online Periodicals Repository Collection: IJBT Vol.02(3) [July 2003]

Role of Acidothermophilic Autotrophs in Bioleaching of Mineral Sulphide Ores

Sat, 28 Jun 2003 22:58:59 GMT

Title: Role of Acidothermophilic Autotrophs in Bioleaching of Mineral Sulphide Ores

Authors: Umrania, Valentina V

Abstract: Living organisms synthesize a wide array of enzymes, which catalyze a myriad of reactions both inside and outside the cell. The acidothermophilic iron-oxidizing bacteria represent a group of obligately autotrophic chemolithotrophs, They include mesophilic Thiobacillus thiooxidans, Leptospirillum ferrooxidans and thermophilic bacteria such as Sulfolobus and Acidianus species. Several studies have shown the importance and feasibility of microbiological prospecting for sulphide ore deposits. Acidothermophilic autotrophic bacteria are now considered as an ideal source to exploit more unusual commercial applications of Geo-biotechnology, especially for metal and mining industry. The mining of copper, uranium, molybdenum, zinc, silver, gold, etc, from their sulphide ores is successfully possible with these microbes. The predominant characteristic of chemolithotrophs is their ability to survive and flourish in a completely inorganic aqueous environment with a supply of oxidizable substrate and CO2, A number of different species have now been isolated from high temperature regions and their potential for the rapid leaching of some ores. The ability of such isolates to tolerate high concentration of toxic heavy metals makes them excellent tools for accumulation and/or for biochemical transformation of metals. The outline of such applications are described in the present review.

Page(s): 451-464

Waste Water Bioremediation in the Pulp and Paper Industry

Sat, 28 Jun 2003 22:58:59 GMT

Title: Waste Water Bioremediation in the Pulp and Paper Industry

Authors: Christov, L; Driessel, B van

Abstract: Effluents from the pulp and paper industry contain chromophoric compounds and can be partly mutagenic and inhibitory to aquatic biosystems. The presence of various pollutants produced during pulp and paper manufacturing necessitates the need for waste water pretreatment prior to discharge. Of all the methods investigated, bioremediation specifically holds promise in solving environmental problems in a cost-effective way. White-rot fungi have ability to process a variety of pollutants efficiently, however, development of suitable cultivation procedures has delayed industrial application. These and other issues affecting bioremediation of industrial wastewater, with special reference to application thereof in the pulp and paper industry, are reviewed in this paper.

Page(s): 444-450

Bioremediation of Metalliferous Wastes and Products using Inactivated Microbial Biomass

Sat, 28 Jun 2003 22:58:59 GMT

Title: Bioremediation of Metalliferous Wastes and Products using Inactivated Microbial Biomass

Authors: Paknikar, K M; Pethkar, A V; Puranik, P R

Abstract: In a developing country like India,. the rush for rapid industrial development coupled with lack of awareness about metal toxicity has become a serious concern to environmentalists. Some technologies, which are used in developed countries for detoxifying metals from industrial effluents, cannot be used in India due to economic constraints. Therefore, there is an urgent need for developing an economical and environment-friendly technology. At the same time, it is essential to prevent the loss of metals through the effluents. The 'Metal Biosorption' process provides a promising alternative method for economical recovery of metals.

Page(s): 426-443

Microbial Pigments

Sat, 28 Jun 2003 22:58:59 GMT

Title: Microbial Pigments

Authors: Joshi, V K; Attri, Devender; Bala, Anju; Bhushan, Shashi

Abstract: The microorganisms such as Monascus, Rhodotorula, Bacillus, Achromobacter, Yarrowia and Phaffia produce a large number of pigments. An ideal pigment-producing microorganism should be capable of using a wide range of C and N sources, have tolerance to pH, temperature and minerals, and give reasonable colour yield. Non-toxic and nonpathogenic nature of pigment-producing microorganisms coupled with easy separation from the cell biomass is stressed. The various advantages of producing pigments from microorganisms include independence from weather conditions, easy and fast growth, colours of different shades and growth on cheap substances. Studies revealed unstable, largely degradable and sensitive to heat, light, acidity and water activity as characteristics of microbial colour. Improvement in stability, safety and solubility can certainly make widespread use of microbial pigments in the food industry.

Page(s): 362-369