Vuosku J.,University of Oulu |
Suorsa M.,University of Oulu |
Ruottinen M.,BioSilta |
Sutela S.,University of Oulu |
And 5 more authors.
Tree Physiology | Year: 2012
Polyamine (PA) metabolism was studied in liquid cultures of Scots pine (Pinus sylvestris L.) embryogenic cells. The focus of the study was on the metabolic changes at the interphase between the initial lag phase and the exponential growth phase. PA concentrations fluctuated in the liquid cultures as follows. Putrescine (Put) concentrations increased, whereas spermidine (Spd) concentrations decreased in both free and soluble conjugated PA fractions. The concentrations of free and soluble conjugated spermine (Spm) remained low, and small amounts of excreted PAs were also found in the culture medium. The minor production of secondary metabolites reflected the undifferentiated stage of the embryogenic cell culture. Put was produced via the arginine decarboxylase (ADC) pathway. Futhermore, the gene expression data suggested that the accumulation of Put was caused neither by an increase in Put biosynthesis nor by a decrease in Put catabolism, but resulted mainly from the decrease in the biosynthesis of Spd and Spm. Put seemed to play an important role in cell proliferation in Scots pine embryogenic cells, but the low pH of the culture medium could also, at least partially, be the reason for the accumulation of endogenous Put. High Spd concentrations at the initiation of the culture, when cells were exposed to stress and cell death, suggested that Spd may act not only as a protector against stress but also as a growth suppressor, when proliferative growth is not promoted. All in all, Scots pine embryogenic cell culture was proved to be a favourable experimental platform to study PA metabolism and, furthermore, the developed system may also be beneficial in experiments where, e.g., the effect of specific stressors on PA metabolism is addressed. © 2012 The Author 2012. Published by Oxford University Press. All rights reserved.
Krause M.,TU Berlin |
Krause M.,University of Oulu |
Neubauer A.,BioSilta |
Neubauer P.,TU Berlin
Microbial Cell Factories | Year: 2016
While the nutrient limited fed-batch technology is the standard of the cultivation of microorganisms and production of heterologous proteins in industry, despite its advantages in view of metabolic control and high cell density growth, shaken batch cultures are still the standard for protein production and expression screening in molecular biology and biochemistry laboratories. This is due to the difficulty and expenses to apply a controlled continuous glucose feed to shaken cultures. New ready-made growth media, e.g. by biocatalytic release of glucose from a polymer, offer a simple solution for the application of the fed-batch principle in shaken plate and flask cultures. Their wider use has shown that the controlled diet not only provides a solution to obtain significantly higher cell yields, but also in many cases folding of the target protein is improved by the applied lower growth rates; i.e. final volumetric yields for the active protein can be a multiple of what is obtained in complex medium cultures. The combination of the conventional optimization approaches with new and easy applicable growth systems has revolutionized recombinant protein production in Escherichia coli in view of product yield, culture robustness as well as significantly increased cell densities. This technical development establishes the basis for successful miniaturization and parallelization which is now an important tool for synthetic biology and protein engineering approaches. This review provides an overview of the recent developments, results and applications of advanced growth systems which use a controlled glucose release as substrate supply. © 2016 The Author(s).
Grimm T.,TU Berlin |
Grimm M.,BIOWORX Biotechnologielabor Thomas Grimm |
Klat R.,BIOWORX Biotechnologielabor Thomas Grimm |
Neubauer A.,BioSilta |
And 3 more authors.
Applied Microbiology and Biotechnology | Year: 2012
The influence of glucose release on growth and biotransformation of yeasts was examined by using the medium EnBase® Flo in shake flasks. The medium contains a polysaccharide acting as substrate, which is degraded to glucose by the addition of an enzyme. In the present paper, this medium was adapted for the cultivation of yeasts by increasing the complex components (booster) and the enzyme concentrations to guarantee a higher glucose release rate. Important changes were an increase of the complex component booster to 10-15% and an increased glucose release by increasing the enzyme content to 15 U L -1. The 20 yeasts investigated in the present work showed an improvement of growth and biomass production when cultivated with the EnBase medium in comparison to yeast extract dextrose (YED) medium. Values of optical densities (OD600) of approximately 40 AU (corresponding to over 60 g L -1 wet cell weight) were achieved for all 20 yeast strains tested. During the following screening of the yeasts in wholecell biotransformation, an improvement of the conversion for 19 out of the 20 yeasts cultivated with the EnBase Flo medium could be observed. The biomass from the EnBase Flo cultivation showed a higher conversion activity in the reduction of 2-butanone to (R/S)- 2-butanol. The enantioselectivity (ee) of 15 yeast strains showed an improvement by using the EnBase medium. The number of yeasts with an ee >97% increased from zero with YED to six with EnBase medium. Thus, the use of a glucose release cultivation strategy in the screening process for transformation approaches provides significant benefits compared to standard batch approaches. © Springer-Verlag 2012.
BioSilta | Date: 2012-01-10
Chemical preparations for scientific purposes, other than for medical or veterinary use. Nutritive substances for microorganisms. Flasks for laboratory use.
BioSilta | Date: 2010-03-04
The present invention is generally in the field of continuous and high-cell-density cultivation in laboratory- or large-scale liquid shaken cultures. More particularly it relates to a method of enzyme-based fed-batch (EnBase) for liquid microbial prokaryotic or eukaryotic cell cultivation having the possibility to manipulate the growth rate of the cultured organisms by a controlled enzymatic release of the growth-limiting substrate-monomer from substrate-polymers or substrate-oligomers.