Use of Medium Concentrates to Improve Bioreactor Productivity

Abstract

Large-scale culture of recombinant mammalian or invertebrate cells requires significant volumes of nutrient medium. Batch preparation of liquid medium from powdered mixtures requires large stainless steel formulation tanks and is labor-intensive. Purchase of large volumes of 1X liquid medium, even in bulk containers, becomes economically unattractive for production of therapeutic quantities of biologicals. We have developed liquid medium concentrate technology which permits traditional synthetic media and serum-free formulations to be prepared in a minimal number of 50X component concentrates. The principles associated with concentrate technology may be extrapolated to a broad range of catalog and custom formulations. Technical advantages include: (1)improved stability of biochemical nutrients, including glutamine; (2)improved solubility of complex media constituents; and (3)enhanced cell growth rate, maximal density, and biological product yield relative to medium prepared directly from powder. Practical considerations include: (1)reduced refrigerated storage space; (2)increased nutrient medium shelf life; (3)improve efficiency of manufacturing facility space utilization; (4)reduced space, labor and equipment costs for media preparation; (5)decreased risk of aerosol-related health hazards and cross-contamination; (6)increased potential medium lot size; (7)reduced quality control testing costs; and (8)enhanced consistency in media formulation between remote manufacturing sites. Liquid medium concentrates appear compatible with large volume bulk containers. Standard mixing protocols permit batch reconstitution into single strength medium. Alternatively, a continuous flow mixing device permits on-line medium reconstitution for perfusion bioreactors.