Trends in Applied Sciences Research1819-35792151-7908Science International10.3923/tasr.2011.1222.1229UgwuC.U. AoyagiH. 102011610This study was aimed at improving the performance of a long outdoor tubular photobioreactor for high yield of algal biomass. A long tubular photobioreactor (with total tube length of approximately 20 m) was developed. In order to understand the performance of the tubular photobioreactor, hydrodynamics and gas-liquid transfer characteristics, as well as outdoor cultivation of microalgae were evaluated. Parameters that were used to evaluate the gas-liquid transfer characteristics of the photobioreactor included the overall mass transfer coefficient (kLa) and mixing time at various aeration rates (i.e., 0.05 to 0.35 vvm). At 0.35 vvm, presence of 8 static mixers on the riser section at a spacing of 1 m increased the kLa by 25 fold and prolonged the mixing time by 2.7 fold compared to that of the photobioreactor without static mixers. By using the tubular photobioreactor without static mixers, the average biomass productivities attained with Synechocystis aquatilis (S. aquatilis) and Chlorella sorokiniana (C. sorokiniana) were 0.55 and 0.35 g/L/day, respectively. However, upon installation of static mixers, biomass productivities of S. aquatilis and C. sorokiniana increased by 27 and 49% (i.e., 0.70 and 0.52 g/L/day), respectively. This study has indicated that efficiency of a 20 m long tubular photobioreactors and outdoor biomass productivities with the photobioreactor can be significantly improved when static mixers were 1 m apart from each other.]]>Fernandez, F.G.A., J.M.F. Sevilla, J.A.S. Perez, E.M. Grima and Y. Chisti,20015627212732Akpolat, O. and S. Eristurk,2008Heamatococcus pluvialis.]]>8763771Azmat, R., Uzma and F. Uddin,200764245Babcock, R.W., J. Malda and J.C. Radway,200214169184Briassoulis, D., P. Panagakis, M. Chionidis, D. Tzenos and A. Lalos et al.,2010Nannochloropsis sp.]]>10167686777Chisti, Y.,200725294306Harith, Z.T., F.M. Yusoff, M. Shariff and A.B. Ariff,2010Chaetoceros calcitrans, during storage.]]>9387391Emily, L.W.T., J. Nandong and Y. Samyudia,2009931263130Garcia-Ochoa, F. and E. Gomez,200927153176Fereshteh, G., B. Yassaman, A.M.M. Reza, A. Zavar and M. Hossein,2007716141619Hoekema, S., M. Bijmans, M. Janssen, J. Tramper and R.H. Wijffels,20022713311338Lee, Y.K. and C.S. Low,1991389951000Hsieh, C.H. and W.T. Wu,200946300305Grima, E.M., F.G.A. Fernandez, F.G. Camacho and Y. Chisti,199970231247Jafari, A.R., M.H. Sarrafzadeh, I. Alemzadeh and M. Vosoughi,2007Aspergillus niger.]]>7270275Oncel, S.S. and O. Akpolat,2006Spirulina platensis.]]>5365372Sauid, S.M. and V.V.P.S. Murthy,20101027452747Torzillo, G., A. Sacchi, R. Materassi and A. Richmond,1991Spirulina platensis grown outdoors in tubular photobioreactors.]]>3103109Ugwu, C.U., J.C. Ogbonna and H. Tanaka,200258600607Ugwu, C.U., J.C. Ogbonna and H. Tanaka,200315217223Ugwu, C.U., J.C. Ogbonna and H. Tanaka,2005Chlorella sorokiniana in inclined outdoor tubular photobioreactors equipped with static mixers.]]>4034063411Ugwu, C.U., H. Aoyagi and H. Uchiyama,20089940214028Weissman, J.C., R.P. Goebel and J.R. Benemann,198831336344Yoshihara, K., H. Nagase, K. Eguchi, K. Hirata and K. Miyamoto,199682351354Zhang, K., N. Kurano and S. Miyachi,20022597101