ORIGINAL PAPER Cultivation of Rubrivivax gelatinosus in fish industry effluent for depollution and biomass production Leandro Kanamaru Franco de Lima • Elisa Helena Giglio Ponsano • Marcos Franke Pinto Received: 16 June 2010 / Accepted: 17 March 2011 / Published online: 27 March 2011 Ó Springer Science+Business Media B.V. 2011 Abstract One application of biotechnology that con- tributes to sustainable development is the utilization of industrial byproducts as substrates for the production of substances of interest by microorganism. In this work, liquid effluent from tilapia fish processing was used as a substrate for the growth of Rubrivivax gelatinosus with the aim of studying the bacterial photo heterotrophic metabolism. Cultivation conditions included 32 ± 2°C, 1,400 ± 200 lux and 7 days. In the initial days, the best cell mass production (0.273 g l -1 with 72 h), specific growth rate (0.188 h -1 with 48 h) and chemical oxygen demand (COD) decrease (43% with 72 h) were reached. Typical bacterial oxycarot- enoids were identified after 3 days of cultivation, averaging 3.03 mg g -1 biomass. Bacterial growth in the effluent dur- ing the period of study resulted in pH increase to 7.9, total nitrogen, oils and greases and COD decreases of 22.46, 47.71 and 52%, respectively, and dry cell mass production of 0.18 g l -1 . The bacterial growth in the wastewater provided biomass and oxycarotenoids and the removal of pollutant load. Keywords Biotechnology  COD  Purple nonsulfur bacteria  Food industry effluent  Oreochromis niloticus  Oxycarotenoids Introduction Tilapia fish (Oreochromis niloticus) cultivation has devel- oped increasingly in Brazil after 1996 and, since 2002, this has been the most cultivated fish species in the country (Boscardin 2008). In 2005, around 38% of continental fish- ing in the country was made up of tilapia, which represented approx. 68 thousand tons (Nogueira 2007). The market segments for this kind of fish in Brazil includes recreational fishing farms, restaurants, industries and exports. Due to continuous development in fish farming and pro- cessing, bulky volumes of liquid effluents rich in organic matters are daily generated and, many times, discharged in coastal waters or rivers without previous treatment (Giord- ano 2004). According to Guerrero et al. (1998), the gener- ation of such effluents in fish industries amounts to 5.4 m 3 for each ton of processed fish, what forces industries to invest in the treatment of residues to avoid environmental impacts, legal punishments and damages to their image. One possible utilization method is bioconversion of these wastewaters into biomass and value-added substances. Rubrivivax gelatinosus (previously named Rhodocyclus gelatinosus) is a phototrophic bacterium that finds a role in the depollution of industrial wastewaters and, concurrently, pro- vides a biomass containing proteins, vitamins and carotenoids that may be used as a feed supplement (Prasertsan et al. 1997; Ponsano et al. 2003, 2004a, b; Kantachote et al. 2005). Studies carried out with the bacterium in poultry slaughterhouse wastewaters showed that it can efficiently grow in that efflu- ent, reducing organic matter and producing oxycarotenoids, without the need for supplementation (Ponsano et al. 2003, 2008). The utilization of these oxycarotenoids as a pigmenting ingredient in poultries feed provided intensification of broilers carcasses and egg yolks coloration (Ponsano et al. 2003, 2004a, b). L. K. F. de Lima (&) Brazilian Agricultural Research Corporation, EMBRAPA Fisheries and Aquaculture, Quadra 103 Sul Av. JK, Cj. 01, Lt. 17, Palmas, TO 77015-012, Brazil e-mail: leandro.kanamaru@embrapa.br E. H. G. Ponsano  M. F. Pinto Faculty of Veterinary Medicine, UNESP, Univ Estadual Paulista, 793 Clo ´vis Pestana, Arac ¸atuba, SP 16050-680, Brazil 123 World J Microbiol Biotechnol (2011) 27:2553–2558 DOI 10.1007/s11274-011-0725-3