Research Article Effect of the Carbon Concentration, Blend Concentration, and Renewal Rate in the Growth Kinetic of Chlorella sp. Adriano Arruda Henrard, 1 Gabriel Martins da Rosa, 1 Luiza Moraes, 1 Michele Greque de Morais, 2 and Jorge Alberto Vieira Costa 1 1 Laboratory of Biochemical Engineering, College of Chemistry and Food Engineering, Federal University of Rio Grande, Italy Avenue on km 8th, P.O. Box 474, 96203-900 Rio Grande, RS, Brazil 2 Laboratory of Microbiology and Biochemical, College of Chemistry and Food Engineering, Federal University of Rio Grande, Italy Avenue on km 8th, P.O. Box 474, 96203-900 Rio Grande, RS, Brazil Correspondence should be addressed to Jorge Alberto Vieira Costa; jorgealbertovc@terra.com.br Received 21 August 2014; Accepted 2 October 2014; Published 15 December 2014 Academic Editor: Takashi Osanai Copyright © 2014 Adriano Arruda Henrard et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te microalgae cultivation can be used as alternative sources of food, in agriculture, residual water treatment, and biofuels production. Semicontinuous cultivation is little studied but is more cost-efective than the discontinuous (batch) cultivation. In the semicontinuous cultivation, the microalga is maintained in better concentration of nutrients and the photoinhibition by excessive cell is reduced. Tus, biomass productivity and biocompounds of interest, such as lipid productivity, may be higher than in batch cultivation. Te objective of this study was to examine the infuence of blend concentration, medium renewal rate, and concentration of sodium bicarbonate on the growth of Chlorella sp. during semicontinuous cultivation. Te cultivation was carried out in Raceway type bioreactors of 6 L, for 40 d at 30 ∘ C, 41.6 mol m −2 s −1 , and a 12 h light/dark photoperiod. Maximum specifc growth rate (0.149 d −1 ) and generating biomass (2.89 g L −1 ) were obtained when the blend concentration was 0.80 g L −1 , the medium renewal rate was 40%, and NaHCO 3 was 1.60 g L −1 . Te average productivity (0.091 g L −1 d −1 ) was achieved with 0.8 g L −1 of blend concentration and NaHCO 3 concentration of 1.6 g L −1 , independent of the medium renewal rate. 1. Introduction Te large-scale commercial microalgae cultivation began in the 1960s in Japan with cultivation of Chlorella, followed in the 70s–90s by the cultivation of Spirulina in Mexico, in USA, and in China. A common feature of most species of microalgae produced commercially (Chlorella, Spirulina, and Dunaliella) is that they grow in selective media and can be grown in open cultivation and still remain relatively free of contamination by other microorganisms [1]. Te microalga Chlorella has GRAS (Generally Recog- nized as Safe) certifcation issued by the FDA (Food and Drug Administration) and can be used as food with no risk to health [2]. Microalgal biomass produced can be exploited as a source of biocompounds with high nutritional and commer- cial value, such as proteins, fatty acids, vitamins, pigments, and biofuels, or in the formulation of foods and animal feed [3]. Trough the years, there is increasing interest in the mass culturing of microalgae for the production of biofuel as well as for use in the pharmaceutical industry, agrochemicals, and animal feed, whereas ways to increasing biomass productivity need to be more investigated and studied to improve com- mercial viability [4]. Cultivation conditions considerably infuence the com- position of microalgae. Several factors can infuence the culti- vation of algae in both open cultivation and closed cultivation such as pH, light, contaminants, temperature, bioreactor type, and the initial concentration of biomass [5–8]. Te mode of operation is directly related to the biotechnological process, because the microorganism needs appropriate conditions to stimulate the synthesis of the desired product. Hindawi Publishing Corporation e Scientific World Journal Volume 2014, Article ID 205184, 9 pages http://dx.doi.org/10.1155/2014/205184