An effect of choline lactate based low transition temperature mixtures on the lipase catalytic properties.

A new series of low transition temperature mixures (LTTM) based on choline lactate quaternary ammonium salt and various hydrogen bond donors was prepared and characterized towards their physicochemical properties and usability as an enzymatic reaction mixture for lipase-catalyzed transesterification reactions. Studies of low transition temperature mixtures have shown a long-term stabilizing effect for lipase as well as a positive influence on lipase thermal stability. In the case of Ch[Lac]:Gly: EthGly increasing the stability of lipase by 8 °C (up to 55.2 °C) compared to the control sample. Conducted transesterification reactions were characterized by high yields - up to 98% - and high purity of the obtained products.

Acceleration of lactose hydrolysis using beta-galactosidase and deep eutectic solvents.

A series of new deep eutectic solvents based on choline levulinate and various hydrogen bond donors were prepared and characterized by1H NMR, FT-IR, TG, and DSC. In particular, their physicochemical properties (density, viscosity, conductivity, and thermal stability) were determined and their usability as an enhancing additive to the enzymatic reaction mixture, for the enzyme was checked. It has been shown, that prepared DES, exhibits low viscosity (at 40 °C within the range 0.1-0.8 Pa·s), high thermal stability (in almost all cases above 150 °C), and density within the range 1.1-1.17 g cm-3. Also, it has been shown, that obtained mixtures can stabilize the enzymes, and positively influence on its activity. The addition of up to 15% (v/v) of DES mixture composed of choline levulinate: ethylene glycol, enhanced more than threefold lactose hydrolysis yield by ß-galactosidase. The present study shows the relevance of the newly designed DES series for improving enzymes properties with the potential to apply in the effective conversion of food processing origin substrates.

Silicone polyether surfactant enhances bacterial cellulose synthesis and water holding capacity.

The versatility and unique properties of bacterial cellulose (BC) motivate research into enhancing its synthesis. Here a silicone polyether surfactant (SPS) was synthesized and tested as a non-nutritional additive to the cultivation media of Komagataeibacter xylinus. The addition of SPS to the Hestrin-Schramm (HS) medium resulted in a concentration-dependent decrease in surface tension from 59.57 ± 0.37 mN/m to 30.05 ± 0.41 mN/m (for 0.1% addition) that was correlated with an increased yield of BC, up to 37% wet mass for surfactant concentration close to its critical micelle concentration (0.008%). Physicochemical characterization of bacterial cellulose obtained in presence of SPS, showed that surfactant is not incorporated into BC structure and has a moderate effect on its crystallinity, thermal stability. Moreover, the water holding capacity was enhanced by over 40%. Importantly, obtained BC did not affect L929 murine fibroblast cell viability. We conclude that SPS provides an eco-friendly approach to increasing BC yield in static culture, enabling more widespread industrial and biomedical applications.

The Simple Method of Preparation of Highly Carboxylated Bacterial Cellulose with Ni- and Mg-Ferrite-Based Versatile Magnetic Carrier for Enzyme Immobilization.

The bacterial cellulose (BC) is a versatile biopolymer of microbial origin characterized by high purity and unusual water and material properties. However, the native BC contains a low number of functional groups, which significantly limits its further application. The main goal of its effective modification is to use methods that allow the unusual properties of BC to be retained and the desired functional group to be efficiently introduced. In the present study, the new magnetic carrier based on functionalized citric acid (CA) bacterial cellulose was developed and tested to support critical industrial enzymes such as lipase B from Candida antarctica and phospholipase A from Aspergillus oryzae. The applied method allowed BC to be effectively modified by citric acid and a sufficient number of carboxylic groups to be introduced, up to 3.6 mmol of COOH per gram of dry mass of the prepared carrier. The DSC and TGA analyses revealed carrier stability at operational temperatures in the range of 20 °C to 100 °C and substantially influenced the amount of the introduced carboxyl groups on carrier properties. Both enzymes' immobilization significantly improves their thermal stability at 60 °C without a significant thermal and pH optima effect. The analyzed enzymes showed good operational stability with a significant residual activity after ten cycles of repeated uses. The new magnetic carrier based on highly carboxylated bacterial cellulose has a high application capability as matrix for immobilization the various enzymes of industrial interest.

The Co-Culture of Staphylococcal Biofilm and Fibroblast Cell Line: The Correlation of Biological Phenomena with Metabolic NMR1 Footprint.

Staphylococcus aureus is one of the most prevalent pathogens associated with several types of biofilm-based infections, including infections of chronic wounds. Mature staphylococcal biofilm is extremely hard to eradicate from a wound and displays a high tendency to induce recurring infections. Therefore, in the present study, we aimed to investigate in vitro the interaction between S. aureus biofilm and fibroblast cells searching for metabolites that could be considered as potential biomarkers of critical colonization and infection. Utilizing advanced microscopy and microbiological methods to examine biofilm formation and the staphylococcal infection process, we were able to distinguish 4 phases of biofilm development. The analysis of staphylococcal biofilm influence on the viability of fibroblasts allowed us to pinpoint the moment of critical colonization-12 h post contamination. Based on the obtained model we performed a metabolomics analysis by 1H NMR spectroscopy to provide new insights into the pathophysiology of infection. We identified a set of metabolites related to the switch to anaerobic metabolism that was characteristic for staphylococcal biofilm co-cultured with fibroblast cells. The data presented in this study may be thus considered a noteworthy but preliminary step in the direction of developing a new, NMR-based tool for rapid diagnosing of infection in a chronic wound.

Deep eutectic solvents based on choline cation - Physicochemical properties and influence on enzymatic reaction with ß-galactosidase.

In presented study analysis of physicochemical properties of deep eutectic solvents (DESs) and their usefulness as an element of reaction medium for ß-galactosidase from Kluyveromyces lactis was conducted. Analyzed DESs were based on choline salt derivatives: choline chloride, choline acetate and hydrogen bond-donors (HBD) such as: glycerol, ethylene glycol, urea, thiourea and levulinic acid. Results showed that reaction medium with appropriate amount of DES based on choline acetate had beneficial effect on activity of ß-galactosidase. The 5% (v/v) addition of developed choline acetate:glycerol DES mixture enhanced enzyme activity almost three fold. The results of performed experiments have also revealed that ß-galactosidase activity is less affected by the organic anion as choline acetate in ionic liquid, than inorganic anion as choline chloride. The developed green solvents as DES based on choline acetate exhibit a wide application potential that can be used to increase efficiency of enzyme-based industrial process.