Open Journal of Applied Sciences, 2012, 2, 146-152 doi:10.4236/ojapps.2012.23021 Published Online September 2012 (http://www.SciRP.org/journal/ojapps) A Comparative Study on Biosorption of Cr(VI) by Fusarium solani under Different Growth Conditions Mousumi Sen Department of Applied Chemistry, Amity School of Engineering & Technology, New Delhi, India Email: mousumi1976@gmail.com Received May 24, 2012; revised June 25, 2012; accepted July 4, 2012 ABSTRACT Biosorption of Cr(VI) from aqueous solution was studied in a batch bioreactor using the resting cells of Fusarium so- lani isolated from soil. The specific Cr(VI) removal decreased with increase in pH from 2.0 to 6.0 and increased with increase in initial Cr(VI) concentration, upto 500 mg·l –1 . By increasing biomass concentration from 2.0 - 5.0 g·l –1 , the specific metal removal remained almost constant. The maximum specific Cr(VI) removal was 60 mg·g –1 achieved at 500 mg·l –1 initial Cr(VI) concentration and by using resting cells (36 h old). The Langmuir adsorption isotherm con- stants, Q o and b were observed to be 57.1 mg·g –1 and 0.06 l·mg –1 respectively. These results were compared with the Cr(VI) removal obtained in earlier studies conducted by the present authors using non living and growing cells of F. solani. Keywords: Biosorption; Cr(VI); Fusarium solani; Resting Cells 1. Introduction Chromium(VI) is one of the toxic heavy metals that are present as chromate  2 4 CrO  hromate  and dic   2 2 7 Cr O  waste water [1] of many industries such as dye, electroplating, metal cleaning, leather, tanneries metal plating, metal cleaning and processing, manufac- ture of anticorrosive agents, wood preservation, wood processing, alloy preparation, pigment manufacture, lea- ther tanning, manufacturing of dyes, printing, etc. [2-4]. The persistant nature of Cr(VI) makes it accumulate in the food chain which with time reach harmful levels in living beings resulting in serious health hazards. There- fore, removal of Cr(VI) from waste water prior to its discharge into natural water systems, adjoining land- masses, sewer systems, etc. requires serious and immedi- ate attention. The conventional treatment techniques used for removal of Cr(VI) from wastewaters are expensive, result in the production of harmful by-products and are not efficient when initial Cr(VI) concentration is in the range of 10 - 100 mg Cr(VI) l –1 [5]. Bioremediation in- volves potential application of microorganisms in re- moval of heavy metals and has been recognized as a po- tential alternative to the conventional methods for treat- ment of contaminated wastewaters [6]. Several research- ers reported removal of Cr(VI) from aqueous solution using growing, resting and non-living cells of different microorganisms [7-19]. in aqueous However, most of the work to remove Cr(VI) have been carried out using non-living fungal cells which have advantages over growing and resting cells due to the ab- sence of both toxicity limitations and requirements for growth media and nutrients. The metal ion uptake by the growing as well as the resting cells, though is a function of cell age, composition of growth media and pH of the solution, the cells can be maintained biologically active to remove Cr(VI) from aqueous solution by maintaining the suitable cell energetic biochemical reaction condi- tions, whereas biochemical reactions are no longer con- tinued in case of non-living biomass as the cells are dried. Further, resting cells have the advantage over growing cells in that the former require very low maintenance energy to remain biologically active. The earlier studies were conducted by the present authors on biosorption of Cr(VI) by using F. solani isolated from soil under dif- ferent growth conditions i.e., resting cells [20] growing cells [21,22] as well as non living biomass [23]. Signifi- cant Cr(VI) removal was observed using growing cells in batch and continuous modes of operations and using non living biomass in batch bioreactor. The present study has been conducted to evaluate the potential of the resting cells of the F. solani for Cr(VI) removal from aqueous solution with an aim to develop suitable operational strategy for treatment of Cr(VI) con- taminated wastewaters. The effects of pH, initial Cr(VI) concentration, biomass concentration and age of the cul- ture on Cr(VI) removal from aqueous a solutions were studied using synthetic Cr(VI) solution in batch bioreac- Copyright © 2012 SciRes. OJAppS