Sphaerotilus+natans+in+wastewater+treatments

//Sphaerotilus natans //in wastewater treatments By: Lucia Mendoza December 7, 2010

**__Abstract: __**

//Sphaerotilus natans //is one of the most common sheathed bacteria found in aqueous habitats. //S. natans// positively as well as negatively affects our environment. //S. natans// has the ability to reduce a very toxic form of chromium that is present in wastewater coming primarily from industries that work with this substance. Chromium hexavalent can be very toxic to all forms of life. //S. natans// can efficiently and economically reduce Cr(VI) to chromium trivalent Cr(III) a more stable form of this substance. It can do so using glucose as an energy source in aerobic batch system under stationary growth conditions (zero growth rate). Whether it will work under different growth factors is under evaluation. //S. natans// can also be a negative factor in our environment especially in sewage treatment plants for it presents a big problem when it clogs the pipes of these facilities.

**__Introduction: __** I chose //to research ////Sphaerotilus natans // //bacteria because I have always been interested in how our wastewater gets recycled and how microorganisms help in the process. // //<span style="color: black; font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; font-style: normal; line-height: 115%;">When I first read about it in our textbook I got the impression that it assisted solely in the process of cleaning up the water, but after performing extensive research I discovered // //<span style="color: black; font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; font-style: normal; line-height: 115%;">that although it does have environmental importance, for it can significantly remove or reduce toxic substances from wastewater, it is actually an economic burden to sewage // //<span style="color: black; font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; font-style: normal; line-height: 115%;">treatment plants because it bulks and clogs pipes. The //<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">purpose of my report is to inform people about, //Sphaerotilus natans, which// are present in many aqueous environments <span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt;">including wastewater treatment plants. I will inform you about its unique characteristics as well as the major impacts it has on our environment.

<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 1in;">**//Sphaerotilus natans//**

**__<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Discussion: __**

**//<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Sphaerotilus natans //**

**__<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Morphology __** //<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Sphaerotilus natans //<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;"> is a filamentous iron bacterium; its filaments consist of chains of rod shaped cells with rounded ends which are enclosed in closely fitting envelopes or sheaths (Stokes,1953). <span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%; margin: 0in 0in 0pt;">The cells that are liberated from the sheaths from time to time may be actively motile by a means of flagella. //S. natans// tends to be pleomorphic, meaning it occurs in two or more different structural forms during a life cycle, depending on the method of cultivation. When isolated from natural habitats, //S. natans// is recognized most easily by its characteristically filamentous colonial form. This form can be considered to be equivalent to the rough or R type. But on cultivation in the laboratory the R type dissociates and gives rise to a smooth or S type (Stokes, 1953).

**__<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Nomenclature __**

//<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Sphaerotilus natans //<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">was first described and named by Kutzing who noted its presence in large numbers in polluted waters. Cohn later discovered it under similar conditions, but because the filaments appeared to be dichotomously branched, although falsely so, Cohn thought that he had found a new organism and accordingly named it //Cladothrix dichotoma// (Stokes, 1953). Both names have been used to describe this microorganism, but further investigations by researchers has shown that //S. natans// exhibits dichotomous false branching whenever it is grown in media of low organic content; therefore, //C. dichotoma// is considered the cladothrix form of //S. natans// (Pringsheim,1949b).

<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%; margin: 0in 0in 0pt;">Names that have been used to describe this bacterium: · //<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Sphaerotilus natans // · //<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Sphaerotilus natans //<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Kutzing · //<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Cladothrix dichotoma //

**__<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Positive Impact on the environment __**

**//<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Sphaerotilus natans’ //****<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">ability to reduce hexavalent chromium: ** <span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%; margin: 0in 0in 0pt;">Chromium can be found in the environment, mainly as Trivalent chromium Cr(III) and hexavalent chromium Cr(VI), its biological effect being highly dependent on its oxidation state. Cr(III) is more stable, less soluble and less toxic than Cr(VI). Cr(VI) is an oxidizing agent highly toxic to all life forms (Caravalli, 2009). The discharge of wastewater effluent and the inadequate disposal of wastes and sub-products coming from several industries which use Cr(VI) have created serious environmental pollution. The World Health organization and the Environmental Protection Agency of the USA have set a maximum limit of Cr(VI) for domestic uses of water (Solisio, 2000) therefore, Cr(VI) must either be reduced or removed in order for the normal flow of water in the sewage treatment plant to continue and for the water to be discharged. The current methods for removing this toxic substance present certain problems; they either create more waste or are economically inconvenient. The Cr(VI) biological reduction constitutes an alternative to the conventional methods used in the detoxification of wastewaters ( Caravalli, 2009). It has been considered a safe, sustainable and economical detoxification process. In a previous work the author of this article, Caravelli reported that //S. natans// is able to reduce <span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%; margin: 0in 0in 0pt;">Cr(VI) to Cr(III) using glucose as an energy source in aerobic batch system under stationary growth conditions (zero growth rate) (Caravalli, 2009). However, its ability to reduce Cr(VI) under different growth conditions has not been evaluated.

<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%; margin: 0in 0in 0pt;">Research in the near future will evaluate the following: <span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%; margin: 0in 0in 0pt 1in; text-indent: -0.25in;">1) The capacity of //S.natans// to reduce Cr(VI) to Cr(III)in a continuous system limited in carbon and energy source or nitrogen source. <span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%; margin: 0in 0in 0pt 1in; text-indent: -0.25in;">2) The toxic effect of Cr(VI) on this microorganism //<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">3) //<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">To carry out a complete analysis of Cr(VI) reduction by //S. natans//

**__<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Negative Impact on wastewater treatment plants __**

**//<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Sphaerotilus natans; //****<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">causative agent for bulking of activated sludge: ** //<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">S. natans, //<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">although an important and helpful organism for many life processes it is also thought of as an economic burden to many wastewater treatment plants. Primarily because it is thought to be a causative agent for bulking of activated sludge (Takahashi, 1990). <span style="color: black; font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">This is highly due to its ability to settle on a solid surface by entanglement or by using an adhesive basal element on one end of the filament (Pellegrin//,// 1999). <span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%;">Although, it aids in the process of recycling water by helping settle the solids present in the primary treatment of wastewater, its consequences are greater once they have clogged a pipe. In order to prevent this from happening, the water is constantly moving which doesn’t allow <span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%; margin: 0in 0in 0pt;">Bacteria like //S. natans// to settle to the bottom and cause problems. <span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: 115%; margin: 0in 0in 0pt;"> <span style="color: black; font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: normal; margin: 6pt 0in;">The following process conditions are favorable to S. natans' growth in activated sludge:


 * <span style="color: black; font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt; tabstops: list .5in;">Low levels of Oxygen, Nitrogen, or Phosphorous
 * <span style="color: black; font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt; tabstops: list .5in;">In the agriculture industry, several low molecular compounds in the influent
 * <span style="color: black; font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt; tabstops: list .5in;">Sludge load > ca. 0.2 kg BOD/kg MLSS.day
 * <span style="color: black; font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt; tabstops: list .5in;">Complete mixing in the aeration tank
 * <span style="color: black; font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt; tabstops: list .5in;">Advantage in high current areas where sheaths allow a means of attachment
 * <span style="color: black; font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt; tabstops: list .5in;">Optimal growth at 86oF Optimal growth at pH 6.4-8.1

<span style="color: black; font-family: 'Arial','sans-serif'; font-size: 12.5pt; line-height: 115%; margin: 0in 0in 10pt;">Literature Cited:

 * 1) AKAHASHI, R., HATTORI, A., INOUE, T., OGIWARA, K., SUZUKI, M., & YONEYAMA, H. (1990). ISOLATION OF SPHAEROTILUS-NATANS LYSING MICROORGANISM FROM ACTIVATED SLUDGE. //Journal of Fermentation and Bioengineering//, //69//(3), 143-147. Retrieved from Biological Abstracts 1969 - Present database.
 * 2) Caravelli, A., & Zaritzky, N. (2009). About the performance of Sphaerotilus natans to reduce hexavalent chromium in batch and continuous reactors. //Journal of Hazardous Materials//, //168//(2-3), Retrieved from Biological Abstracts 1969 - Present database.
 * 3)  Chen, H., Ponniah, G., Salonen, N., Blum, P. (2004). Culture-Independent Analysis of Fecal Enterobacteria in Environmental Samples by Single-Cell mRNA Profiling. //<span style="font-family: 'Arial Narrow','sans-serif';">Appl. Environ. Microbiol. // 70: 4432-4439
 * 4) Pellegrin, Veronique, Stefan Juretschko, Michael Wagner, and Gilles Cottenceau. 1999. "Morphological and biochemical properties of a Sphaerotilus sp. isolated from paper mill slimes." Appl Environ Microbiol, vol. 65, no. 1. American Society for Microbiology. (156-162)
 * 5) Solisio, C., Lodi, A., Converti, A., & Del Borghi, M. (2000). The effect of acid pre-treatment on the biosorption of chromium(III) by Sphaerotilus natans from industrial wastewater. //Water Research//, //34//(12), 3171-3178. Retrieved from Biological Abstracts 1969 - Present database.
 * 6)  Tortora, Gerard J., Funke Berdell R., and Case L. Christine. //<span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt; letter-spacing: 2pt; line-height: 115%;">Microbiology an Introduction // . 10th ed. San Francisco: Pearson Education Inc, 2010. 1-812.Tanya & Lucia