P63: Gaining critical process knowledge at shake flask scales: Measuring respiration activity in nutrient-limited fed-batch shaken cultures

Small scale bioreactors deliver scalable results at upstream screening stages. Unfortunately, due to constraints including limited throughput, high investment and ongoing operation costs, these systems are not used ubiquitously for front-line screening efforts.

An alternative approach for generating scalable data from upstream screening steps is to better characterize, understand and implement platforms already in use. Well plate and shake flask experiments can properly rank clones and identify process bottlenecks if process data is collected to validate system performance and carefully design the screen. One tool available to gain process knowledge of flasks and other shaken vessels is the Respiration Activity MOnitoring System (RAMOS) – which allows simple online measurement of respiration / fermentation activity in shaken bioreactors. RAMOS reports the respiratory quotient of cultures under standard screening conditions - and can be adapted to most shaken vessels. When combined with technologies such as FeedBeads – RAMOS reveals deficiencies in media recipes, cultivation conditions, strain performance or construct performance (among others). Identifying problems in flask systems allows researchers to improve their flask scale work. Data here highlights the use of RAMOS for media design and identification of substrate limitation, oxygen limitation, product inhibition and diauxic growth.  Data will also show use of RAMOS in combination with slow-release glucose discs (FeedBeads) for establishment of fed-batch growth in shake flasks.