Porous polypeptide-based hydrogels as a matrices for stem cells attachment

New Biotechnology · Volume 29S · September 2012

been avoided because of the risk of their harmful effects on the human body [2]. In this study, the activated carbon with the chemical activation of ZnCl2 was prepared from the corn cob. Corn cob charcoal supporting silver (CC/Ag) was prepared by activation and chemical reduction. The chemical and physical properties of CC/Ag composites were examined by XRD, FTIR, SEM, BET. The antimicrobial effects of characterized composites were determined against Escherichia coli. Scanning electron microscopy (SEM) showed that the Ag particles were distributed uniformly on the CC matrix. The Ag content and surface morphology of the BC/Ag composites depended on the initial concentration of AgNO3 , and the higher the Ag content, the smaller the specific surface area obtained on the CC. A good antimicrobial performance of the CC/Ag composite powders was discovered against E. coli.

References 1. Oliveira LCA, et al. Preparation of activated carbons from coffee husks utilizing FeCl3 and ZnCl2 as activating agents. J Hazard Mater 2009;165:87–94. 2. Dastjerdi R, Montazer M. A review on the application of inorganic nano-structured materials in the modification of textiles: focus on anti-microbial properties. Colloids Surf B: Biointerfaces 2010;79:5–18.

http://dx.doi.org/10.1016/j.nbt.2012.08.157 Poster 1.3.13 Study of strains brevibacterium as producer of lysine G. Andriiash ∗ , G. Zabolotna, S. Shulga Institute for Food Biotechnology and Genomics. National Academy of Science of Ukraine, 2а, Osypovskogo str., 04123 Kyiv-123, Ukraine Investigations of lysine producer strains from Institute for Food Biotechnology and Genomics “Collections of microbial strains and plant lines for food and agricultural biotechnology” were carried out. Clonal analysis of the strains was done after batch fermentation of producers on molasses medium. It was found that Brevibacterium sp. 90, Brevibacterium sp. 90H, and Brevibacterium sp. XI strains gave colonies splitting into two types. All the clones were estimated by biosynthetic activity relatively lysine. Mutational changes were observed in the clones some of which remained dependent on leucine and get a new auxotrophity for threonine, methionine, tryptophan, isoleucine and homoserine. It was shown that only some clones were resistant to S-amino-ethyl-L-cysteine – analogue of lysine. Clones on biosynthetic activity relative to the target amino acid were selected for further research with the aim to improve lysine biosynthesis by Brevibacterium producer strains. Culture conditions were optimized for two clones that are maximum lysine producing and resistant to S-amino-ethyl-L-cysteine. Keywords: Amino acids; Auxotrophity; Biosynthesis; Clones; Lysine http://dx.doi.org/10.1016/j.nbt.2012.08.158

Poster 1.3.14 Porous polypeptide-based hydrogels as a matrices for stem cells attachment H. Studenovska 1,∗ , T. Sedlacik 1 , V. Proks 1 , Ö. Karabıyık 2 , M. Ramazano˘ glu 2 , G.T. Köse 2 1

Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague, Czech Republic 2 Yeditepe University, Faculty of Engineering and Architecture, Department of Genetics and Bioengineering, 26 Agustos Campus, Kayısdagı, Istanbul, Turkey The aim of this project is investigation of cartilage differentiation from dental follicle stem cells (DFC) on porous poly(alpha-amino acid)s (PAAs) hydrogels. Scaffolds based on synthetic PAAs belong to promising biomaterials combining advantages of natural and synthetic matrices. PAAs, due to their polypeptide backbone are prone to enzymatic hydrolysis, which can be controlled through copolymerization or modification of PAA side chains. In addition to adjustable enzymatic degradability we can also benefit from good modification options that synthetic PAAs offer, to introduce covalently bound specific peptide motives, (RGDS), through which interactions of cells via their integrin receptors with synthetic PAA hydrogels could be promoted. The porous design of three-dimensional structure of scaffolds could follow the requirements for materials applicable in tissue regeneration. Porous hydrogels were prepared by two techniques: (A) the covalently crosslinked gels were formed by radical copolymerisation of methacryloylated macromonomer poly[N5 -(2-hydroxyethyl)L-glutamine-stat-L-alanine-stat-methacryloyllysine] as a multifunctional macro-monomer with 2-hydroxyethylmethacrylate (HEMA) as minor comonomer using 2,2 -azobisisobutyronitrile as initiator. The porosity in hydrogel was formed by phase separation of fraction of polyHEMA. The size of pores ranged from 5–20 microm. (B) In second technique the porosity in hydrogels was formed during cryogelation. Covalently crosslinked hydrogels based again on methacryloylated poly[N5 -(2-hydroxyethyl)-Lglutamine were prepared at −19 ◦ C. The porosity of cryogels is ca 100 microm. Both types of hydrogels were prepared as blank ones or modified with RGDS groups. Cell-seeding experiments using DFC show a good potential of the described macroporous gels as a soft tissue scaffolds. Acknowledgements: Financial support of P108/12/1538 and ASCR-TUBITAK (111M031). http://dx.doi.org/10.1016/j.nbt.2012.08.159 Poster 1.3.15 Immobilized enzymes for antibiotic production I.Yu. Galaev 1,∗ , T. van der Does 2 , E. van de Sandt 1 1

DSM Biotechnology Center, Netherlands DSM Sinochem Pharmaceuticals, Alexander Fleminglaan 1, 2613 AX Delft, Netherlands

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Immobilized enzymes (IE) despite obvious advantages and considerable academic research in the area have so far found only few applications in large scale industrial processes. Few factors www.elsevier.com/locate/nbt S57