GROWTH ON MICROCARRIERS AND NUTRITIONAL NEEDS OF HIGH DENSITY INSECT CELL CULTURES L. IKONOMOU 1 , G. BASTIN 2 , Y.-J. SCHNEIDER 3 , and S.N. AGATHOS 1 1 Unit of Bioengineering, Catholic University of Louvain, Place Croix du Sud 2/19, B-1348, Louvain-la-Neuve, Belgium 2 Centre for Systems Engineering and Applied Mechanics, Av. George Lemaître 4, Catholic University of Louvain, B-1348, Louvain-la-Neuve, Belgium 3 Laboratory of Cellular Biochemistry, Catholic University of Louvain, Place L. Pasteur 1, B-1348, Louvain-la-Neuve, Belgium 1. Introduction The insect cell/baculovirus (ICB) system has become popular both for the production of recombinant proteins and biopesticides. The development of serum-free media, advances in baculovirus vector construction and the relative simplicity of insect cell culture make the ICB quite powerful and versatile for recombinant protein expression. We report here experimental results on the growth of insect cells in bioreactor. The evaluation of insect cell growth on Fibra-Cel ® microcarriers in suspension is also presented. 2. Materials and Methods Sf9 and High Five™ cells were a gift from SmithKline Beecham, Belgium and from the Laboratory of Virology, Agricultural University of Wageningen, Netherlands, respectively. The SF-900 II and Insect XPRESS media were purchased from Life Technologies and BioWhittaker Europe. Metabolite levels were determined using enzymatic kits from Boehringer Mannheim. Amino acid quantification was performed by HPLC. The bioreactor used in this study was Celligen Plus ™ (New Brunswick Scientific), with working volume of 1 l and Insect XPRESS medium. Oxygen level was set at 50% of air saturation and aeration was performed via the headspace. Fibra-Cel ® disks from Bibby Sterilin were employed. They were evaluated in siliconised 250-ml disposable Erlenmeyer flasks containing 50 ml of medium and kept at 100 rpm and 27°C. Half of the medium was changed on day 3, 6 and 8 for Sf9 and on day 3 and 6 for High Five ™ cells. All of the medium was changed on day 8 in the flasks containing High Five ™ cells. Disk samples were incubated for 2 h with crystal violet (0.1% w/v) dissolved in citric acid (0.1 M) and Triton X-100 (0.1% v/v). 371 A. Bernard et al. (eds.), Animal Cell Technology: Products from Cells, Cells as Products, 371–373. © 1999 Kluwer Academic Publishers. Printed in the Netherlands.