Elisa Helena Giglio Ponsano1, Leandro Kanamaru Franco de Lima2

and Ane Pamela Capucci Torres1

1Unesp Univ Estadual Paulista, Faculty of Veterinary Medicine, Aragatuba,

2Brazilian Agricultural Research Corporation, Embrapa Fisheries and Aquaculture, Palmas,

Brazil

1. Introduction

Industrial activities have always been associated to the economic development of nations and their population. Nevertheless, they are also associated to the generation of industrial byproducts, generally considered undesirable due to the environmental damage they impose to society (Pipatti et al., 2009). Industrial byproducts have variable characteristics and compositions, since they are directly dependent on crude matter essence, kind of processing, facilities characteristics and volume of output, among so many other factors. Nowadays, the broad range of industries spread all over the world in an effort to supply the necessity of global population makes evident the need for the adoption of strategies capable of equilibrating economic development and environmental preservation as a way of reaching a sustainable industrial production (Parente & Silva, 2002).

In that way, transformation industries are currently searching for productive technologies of low environmental impact, which include practices like minimization of byproducts generation and/or recuperation and recycling of these residues, so aiming at the optimization of industrial processes (Juskaite-Norbutiene et al., 2007; Leite & Pawlowsky, 2005; Souza & Silva, 2009). The adoption of such technologies is a differential for the establishment and maintenance of industries in the current social and economic world scenery (Leite & Pawlowsky, 2005).

The management of industrial byproducts generally combines techniques as recuperation, treatment and safe disposal. Regarding to liquid waste, also called wastewater or effluent, treatments performed in the food industry generally consist of physical, chemical and biological operations. Physical treatments provide the removal of suspended solids and the separation of oils and fats by means of filtration, grading, sedimentation or floating techniques, while chemical treatments provide the removal of dissolved matter and even of microorganisms by using different chemicals (Giordano, 2006). The biological treatments, in turn, count on the ability of bacteria, fungi, micro algae and protozoa in transforming organic matter into new cells, called biomass, and gases (Arvanitoyannis & Tserkezou, 2009; Giordano, 2006). This kind of treatment simulates the natural remediation processes that occur in nature and brings as an advantage the production of compounds with particular applications, which may be appropriately separated and used for distinct purposes (Liu, 2007). Microbial biomass, for instance, has been considered as an alternative source of

proteins for foods and feeds and may be produced in different substrates, including effluents from industries and farms (Nasseri et al., 2011).

Some organisms may be used for the removal of organic matter from agro industrial residues yielding a biomass with potential for use in animal feeding, such as the phototrophic bacteria (Azad et al., 2003; Izu et al., 2001; Ponsano et al., 2008). Purple Non Sulfur Bacteria (PNSB), for example, are phototrophic bacteria commonly found in rivers, ponds, lakes and wastewater treatment systems, that can grow both as photoautotroph and photoheterotroph under anaerobic-light or microaerobic-light conditions (Choorit et al., 2002; Kantachote et al., 2005). Some PNSB also can grow in the dark using fermentation when they are in anaerobic environments or respiration when in aerobiosis (Devi et al., 2008; Kantachote et al., 2005; Kim et al., 2004; Ponsano et al., 2002a). Due to the ability of phototrophic bacteria to utilize diverse metabolic activities in different substrates and growth conditions, they find a role in the depollution of wastewaters from food industries, still producing a biomass rich in proteins, vitamins and carotenoids that may be used in the supplementation of animal feed (Carlozzi & Sacchi, 2001; Izu et al., 2001; Kantachote et al., 2005; Ponsano et al., 2002a, 2003a, 2004a, b; Zheng et al., 2005 a, b).

Rubrivivax gelatinosus, formerly named Rhodocyclus gelatinosus is a PNSB commonly found in many wastewaters in which it grows as an autotrophic or a heterotrophic, depending on light and oxygen conditions (Ponsano et al., 2003a, 2008). As the bacterium produces oxycarotenoids as photosynthetic pigments, its biomass can find use as a pigmenting additive in animal production, as previously suggested and tested by Ponsano et al. (2002b, 2003b, 2004a, b) and Polonio et al. (2010).

The use of pigmenting additives in animal production is justified by the fact that animals are unable to synthesize their own carotenoids and therefore, rely on dietary supply to achieve their natural pigmentation (Gouveia et al., 2003). The effectiveness of oxycarotenoids or xanthophylls in providing pigmentation to animals is possible because these carotenoids have the ability to deposit on different parts in animal bodies, such as muscles, fat, skin, feather, legs, ovaries and eggs (Ponsano et al., 2002b, 2004b).

Primarily, pigmenting additives were added into food formulations in order to replace color lost during the industrialization processes but, when the remarkable acceptance of consumers for well colored products was identified, industries started coloring a broad range of food items, reaching consumers desire and so improving its sales (Calil & Aguiar,

1999) . In case of poultry and fish production, for instance, either natural or synthetic additives are used when intensive rearing is adopted and/or when feed ingredients are poor in xanthophylls, so lacking in color in the final products. The most used synthetic additives for this purpose are apocarotenoic acid ethyl ester, canthaxanthin and astaxanthin, which show good stability and deposition rates on animal tissues. Nevertheless, more and more consumers around the world have been showing their preference for natural additives, what stimulates the search for natural sources of pigments, like those from biotechnological production. Among natural xanthophylls used in animal production, those from plants, algae, bacteria and yeasts have been previously described in literature (Akiba et al., 2000, 2001; Bosma et al., 2003; Gouveia et al., 1996; Liufa et al., 1997; Perez-Vendrell et al., 2001; Toyomizu et al. 2001).

The great acceptance that fish finds among consumers due to its nutritional and sensorial properties guarantees its market and yet claims for increases in production, which has been supplied by the aquaculture (Lem & Karunasagar, 2007). Nevertheless, fish is a perishable food and so requires the application of methods for its preservation, such as fermentation, refrigeration, freezing, canning, smoking, drying and others, that may be performed separately or in combinations. As it happens in any other food industry, fish processing generates great amounts of wastewaters with variable Chemical Oxygen Demand which depends on fish species, fish products and methods of processing, since water is involved in several stages of manufacturing, like butchering, evisceration, filleting, salting, cooking, canning, freezing, sterilization and cleaning operations (Arvanitoyannis & Kassaveti, 2008; Liu, 2007). The utilization of these effluents for the biomass production is an alternative for minimizing costs with treatment and environmental impacts. Moreover, in case the composition of the biomass finds an appropriate purpose, it can represent extra profits for the industry.

So, the hypothesis to be tested in this chapter is that an industrial byproduct may undergo a biological treatment yielding a product with application. The objective of this chapter was to describe a study on the transformation of a fish processing wastewater into a product with potential of use in animal rearing.