Scale-Up of Capsular Polysaccharide Production Process by Haemophilus influenzae Type b Using kLa Criterion

Abstract

Polyribosyl-ribitol-phosphate (PRP) from Haemophilus influenzae type b (Hib) is an active immunizing molecule used in the production of the vaccine against H. influenzae, and industrial production could contribute to satisfying a world demand especially in developing countries. In this sense, the aim of this study was to establish a scale-up process using the constant oxygen mass transfer coefficient (kLa) such as the criterion for production of PRP in three different sizes of bioreactor systems. Three different kLa values (24, 52 and 80 h−1) were evaluated in which the biological influence in a 1.5 L bioreactor and 52 h−1 was selected to scale-up the production process until a 75 L pilot-scale bioreactor was achieved. Finally, the fed-batch phase was started under a dissolved oxygen concentration (pO2) at 30% of the saturation in the 75 L bioreactor to avoid oxygen limitation; the performance of production presented high efficiency (9.0 g/L DCW-dry cell weight and 1.4 g/L PRP) in comparison with previous scale-up studies. The yields, productivity and kinetic behavior were similar in the three-size bioreactor systems in the batch mode indicating that kLa is possible to use for PRP production at large scales. This process operated under two stages and successfully produced DCW and PRP in the pilot scale and could be beneficial for future bioprocess operations that may lead to higher production and less operative cost.

Effects of Oxygen Transference on Protease Production by Rhodotorula mucilaginosa CBMAI 1528 in a Stirred Tank Bioreactor

“…The stage for establishing conditions can be carried out in shake flasks or bioreactors, despite the fact that the physical and biological factors would be different in these systems. The selection of design conditions and operational procedures is very important to expand the process and to ensure that the effect of the variables on the process are the same [ 40 ]. The scaling up of the fermentation processes from the laboratory-scale to commercial units is challenging due to the difficulty in assessing the factors of influence during cultivation [ 49 ].…”

“…In this sense, aerobic bioprocess development using R. mucilaginosa should be carried out to avoiding oxygen limitation. The evaluation of constant volumetric mass transfer coefficient ( k L a ) is an important step in order to supply adequate oxygen transfer, mixing/sparging operation, and scaling-up criterion [ 39 , 40 ] due to effects in physical and biological characteristics related with metabolic pathways for growing and product formation [ 41 , 42 ]. Thus, the aim of this work was to investigate the effect of the volumetric oxygen mass transfer coefficient ( k L a ) on aspartic protease production during the cultivation of marine Antarctic R. mucilaginosa CBMAI 1528 in a stirred tank bioreactor.…”