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Operational patterns affecting lactic acid production in ultrafiltration cell recycle bioreactor
Author(s) -
Xavier A. M. R. B.,
Gonçalves L. M. D.,
Moreira J. L.,
Carrondo M. J. T.
Publication year - 1995
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260450406
Subject(s) - lactic acid , dilution , bioreactor , membrane , ultrafiltration (renal) , chemistry , chromatography , sterilization (economics) , permeability (electromagnetism) , chemostat , membrane reactor , pulp and paper industry , chemical engineering , biochemistry , biology , bacteria , organic chemistry , engineering , physics , genetics , foreign exchange , monetary economics , economics , foreign exchange market , thermodynamics
Lactic acid production with cell recycling on an ultrafiltration tubular membrane reactor was studied; higher lactic acid concentrations as well as productivities were obtained under long‐term fermentations compared with other high cell density systems. Different operational conditions, namely dilution rates and start‐up modes, were assessed. Performances were very different at the three different dilution rates tested ( D = 0.20 h −1 , D = 0.40 h −1 , or D = 0.58 h −1 ). The different behaviours are discussed and factors responsible for them are presented. The best way to operate for lactic acid production is chosen, the dilution rate of D = 0.40 h −1 being the one providing the best overall performance. On the other hand, results show that of the two start‐up modes tested, continuous start (membrane open) permits higher permeabilities throughout the operational runs than batch start (membrane closed). Operational stability was found to be directly associated with membranes that work at “steady state,” the membrane permeability being kept around 15 L/m 2 h. Optimized cell bleed can improve time of operation if such membrane permeability can be maintained for a longer time. A comparison of results with those obtained in other lactic acid production systems is presented; such comparison shows that this tubular ultrafiltration membrane cell recycle reactor presents three important advantages: (1) concomitant lactic acid concentrations and productivities; (2) long periods of operation at reasonable permeabilities; and (3) good mechanical stability permitting the use of steam sterilization. © 1995 John Wiley & Sons, Inc.