Interfacing Pichia pastoris cultivation with expanded bed adsorption
2006 (English)In: Biotechnology and Bioengineering, ISSN 0006-3592, E-ISSN 1097-0290, Vol. 93, no 6, 1040-1049 p.Article in journal (Refereed) Published
For improved interfacing of the Pichia pastoris fed-batch cultivation process with expanded bed adsorption (EBA) technique, a modified cultivation technique was developed. The modification included the reduction of the medium salt concentration, which was then kept constant by regulating the medium conductivity at low value (about 8 mS/cm) by salt feeding. Before loading, the low conductivity culture broth was diluted only to reduce viscosity, caused by high cell density. The concept was applied to a one-step recovery and purification procedure for a fusion protein composed of a cellulose-binding module (CBM) from Neocallimastix patriciarum cellulase 6A fused to lipase B from Candida antarctica (CALB). The modified cultivation technique resulted in lower cell death and consequently lower concentration of proteases and other contaminating proteins in the culture broth. Flow cytometry analysis showed 1% dead (propidium-stained) cells compared to 3.5% in the reference process. During the whole process of cultivation and recovery, no proteolysis was detected and in the end of the cultivation, the product constituted 87% of the total supernatant protein. The lipase activity in the culture supernatant increased at an almost constant rate up to a value corresponding to 2.2 g/L of CBM-CALB. In the EBA process, no cell-adsorbent interaction was detected but the cell density had to be reduced by a two-times dilution to keep a proper bed expansion. At flow velocity of 400 cm/h, the breakthrough capacity was 12.4 g/L, the product yield 98%, the concentration factor 3.6 times, the purity about 90%, and the productivity 2.1 g/L (.) h.
Place, publisher, year, edition, pages
2006. Vol. 93, no 6, 1040-1049 p.
Pichia pastoris, fed-batch processes, expanded bed adsorption, cellulose-binding domain, saccharomyces-cerevisiae, protein-purification, recombinant proteins, vacuolar proteases, fusion protein, expression, chromatography
IdentifiersURN: urn:nbn:se:kth:diva-15583DOI: 10.1002/bit.20811ISI: 000236592200002ScopusID: 2-s2.0-33646045883OAI: oai:DiVA.org:kth-15583DiVA: diva2:333624
QC 201005252010-08-052010-08-05Bibliographically approved