Use of several yeast and moulds to biodegradation of modified polyurethane foams—A screening study

S174

Abstracts / Journal of Biotechnology 131S (2007) S133–S187

Nitschcke, M., Pastore, G.M., 2003. Appl. Biochem. Biotechnol. 105, 295–302. Sen, 1997. J. Chem. Tech. Biotechnol. 68, 263–270.

doi:10.1016/j.jbiotec.2007.07.906 77. Use of several yeast and moulds to biodegradation of modified polyurethane foams—A screening study Martina Carnecka ∗ , Stanislav Obruca, Vladimir Ondruska, Lada Hlobilova, Jana Hrdlickova, Marie Trckova, Ivana Marova Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic Biodeterioration and biodegradation of polymeric materials affect a wide range of industries. Degradability of polymeric materials is generally a function of the structure, the presence of microbial population and the environment. Very small variations in the chemical structures may result in large differences in term of biodegradability. Polymers are potential substrates for heterotrophic microorganisms including bacteria and fungi. Dominant groups of microorganisms and the degradative pathways associated with polymer degradation are often determined by the environmental conditions. Aerobic processes are capable of supporting a greater population of microorganisms than anaerobic processes. In this work, several types of polyurethane foams (PUR) modified by polysaccharide or protein component (10% of acetyl-, hydroxyethyl- and carboxymethyl cellulose, 1–10% activated starch, 1–5% glutein) were prepared. Single cultures of Aureobasidium pullulans and Fusarium solani and also model composting conditions enriched by these cultures were used to biodegradation of modified materials. First, in single strain cultures, all materials were tested as potential carbon/nitrogen source. Further, microorganisms were cultivated for 4–6 weeks in presence of PUR under permanent shaking. In regular intervals growth characteristics were determined, chemical oxygen demand was evaluated and loss of PUR mass was determined gravimetrically. Additionally, surface microscopy of all degraded polyurethanes was tested. Degradation degree of modified foams corresponded with growth of both microbial cultures. The highest degree of degradation by bacteria was found in PUR modified by activated starch, high biodegradation exhibited also polyurethanes modified by HEC and glutein. As the most stable structure in all microbial systems was found PUR modified by acetyl cellulose. Yeasts were less active in biodegradation than moulds, however, substantial adsorption of cells on PUR surface was observed. In A. pullulans significant dependence of exopolysacharides and/or pigment formation on type of modified filler in BIO-PU was observed. According to type BIO-PUR different sorption ability of Aureobasidium cells on polyurethane foam surface was observed. This fact could be important for potential use for cell immobilisation. Under composting conditions, the biodegradation of all PUR foams was quite slower than in Erlemayer flasks. It seems, that surface hydrophobicity, which is related to good adhesion of microorganisms on the poly-

mer surface, is considered to be a factor of biodegradation rate. In conclusion, microbial cultures can be used to biodegradation of modified polyurethanes; degree of degradation is strongly dependent on type of modification agents and microorganisms. Acknowledgement: This work was supported by project MSM 0021630501 of Czech Ministry of Education. doi:10.1016/j.jbiotec.2007.07.907 78. On-line data reconciliation of mid-infrared and dielectric spectral measurements for the estimation of analyte and biomass concentrations in microbial fermentations Michal Dabros 1,∗ , Michael Amrhein 1 , Paman Gujral 1 , Ian Marison 2 , Urs von Stockar 1 1 Ecole

Polytechnique F´ed´erale de Lausanne, Lausanne, Switzerland 2 Dublin City University, Dublin, Ireland On-line data reconciliation of spectral measurements is typically used to improve the accuracy of concentration estimates of process analytes in monitoring and process control applications. Here, a Fourier-transform mid-infrared spectrometer (FTIR) runs in parallel with a dielectric spectrometer (Biomass Monitor) estimating the concentrations of the main medium analytes and the biomass concentration in experimental microbial fermentations, respectively. In earlier studies, it was found that the corresponding calibration models built off-line suffer from increased estimation errors in subsequent runs due to various factors such as instrumental baseline shifts, signal instability and variations in process conditions unseen during calibration. To address the problem, the estimated values from the calibration models are reconciled in real-time using mass and elemental balances based on supplementary process measurements available routinely during the run. The proposed method leads to decreased errors of the concentration estimates of the medium analytes and biomass with no additional sampling or off-line analysis. doi:10.1016/j.jbiotec.2007.07.908 79. Overexpression of human procarboxypeptidase B by fedbatch cultuivation of recombinant Mi-JIn Kim 1,∗ , Jae Hyung Lee 1 , Jong-Hwan Lee 2 , Jin-Ho Seo 3 , Soo-Wan Nam 2 1 Department Biomaterial Control, Dong-Eui University, Busan, 614-714, Republic of Korea 2 Department Biomaterial Control/Department Biotechnology and Bioengineering, Dong-Eui University, Busan, 614-714, Republic of Korea 3 Department Agricultural Biotechnology, Seoul National University, Seoul, 151-742, Republic of Korea

Pancreatic carboxypeptidase is zinc-metalloenzyme that hydrolyzes the C-terminal amino acids from alimentary pro-