The accumulation of polyhydroxyalkanoates (PHAs) by microorganisms usually occurs in response to environmental stress conditions. Therefore, it is advantageous to choose two-step cultivation. The first phase is aimed at maximizing biomass production, and only in the second phase, after setting the suitable conditions, PHA production starts. The aim of this work was to optimize the composition of the minimal propagation medium used for biomass production of Cupriavidus necator DSM 545 using the response surface methodology (RSM). Based on the results from the search for optimization limits, the glucose concentration, the ammonium sulfate concentration and the phosphate buffer molarity were chosen as independent variables. The optimal values were found as follows: the glucose concentration 10.8 g/L; the ammonium sulfate concentration 0.95 g/L; and the phosphate buffer molarity 60.2 mmol/L. The predicted biomass concentration was 4.54 g/L, and the verified value was at 4.84 g/L. Although this work was primarily focused on determining the optimal composition of the propagation medium, we also evaluated the optimal composition of the production medium and found that the optimal glucose concentration was 6.7 g/L; the ammonium sulfate concentration 0.60 g/L; and the phosphate buffer molarity 20 mmol/L. The predicted PHB yield was 54.7% (w/w) of dry biomass, and the verified value was 49.1%.

This review aims to provide a comprehensive overview of the application of bacterial and fungal laccases for the removal of pharmaceuticals from the environment. Laccases were evaluated for their efficacy in degrading pharmaceutical substances across various categories, including analgesics, antibiotics, antiepileptics, antirheumatic drugs, cytostatics, hormones, anxiolytics, and sympatholytics. The capability of laccases to degrade or biotransform these drugs was found to be dependent on their structural characteristics. The formation of di-, oligo- and polymers of the parent compound has been observed using the laccase mediator system (LMS), which is advantageous in terms of their removal via commonly used processes in wastewater treatment plants (WWTPs). Notably, certain pharmaceuticals such as tetracycline antibiotics or estrogen hormones exhibited degradation or even mineralization when subjected to laccase treatment. Employing enzyme pretreatment mitigated the toxic effects of degradation products compared to the parent drug. However, when utilizing the LMS, careful mediator selection is essential to prevent potential increases in environment toxicity. Laccases demonstrate efficiency in pharmaceutical removal within WWTPs, operating efficiently under WWTP conditions without necessitating isolation.

Microorganisms and plants can be important sources of many compounds with potential pharmaceutical applications. Extraction of these matrices is one of the ways of identifying the presence of inhibitory active substances against enzymes whose high activity leads to serious human diseases including cancer, Parkinson's or Crohn's diseases. The isolation and purification of inhibitors are time-consuming and expensive steps in the analysis of the crude extract and therefore, it is necessary to find a fast, efficient, and inexpensive method for screening extracts of interest. TLC-Bioautography combines the separation of the extract on a thin layer with its subsequent biological analysis. TLC-Bioautography methods have been developed for several classes of enzymes including oxidoreductases, hydrolases and isomerases, and there is a potential for developing functional methods for other classes of enzymes. This review summarizes known TLC-Bioautography methods and their applications for determining the presence of enzyme inhibitors in extracts and compares the effectiveness of different methodological approaches. It also indicates the current state and perspective of the development of TLC-Bioautography and its possible future applications.

The aim of this work was to identify the main microbiota in raw cow milk from dairy farm of Slovakia and to describe the selected microorganisms responsible for thermostable protease and lipase production which can affected the quality of dairy products. The main bacterial classes identifying by MALDI-TOF MS were Gammaproteobacteria (62 %), Actinobacteria (19 %) and Bacilli (12 %). The dominant microbial genus of raw cow milk was Pseudomonas. From milk bacteria, the strain Lactococcus lactis and from the family Enterobacteriaceae, namely Enterococcus faecalis, Hafnia alvei, Citrobacter braakii and Raoultella ornithinolytica were observed in raw milk. The spoilage of milk products is caused by thermostable enzymes with lipolytic and proteolytic activity. Qualitative proteolytic and lipolytic activities were performed on skin milk agar and olive oil, respectively. From 16 identified microorganisms, only 8 strains (P. fragii, P. gessardii, P. lundesis, H. alvei, C. braakii, R. ornithinolytica, Kocuria rhizophila and Candida inconspicua) showed protease activity. Quantitative protease and lipase activities were determined by casein and olive oil, respectively. The highest both activities were measured for the genus Pseudomonas. While lipases produced by all isolated microbial species lose enzymatic activity at 77 °C for 30 – 40 min, almost proteases showed comparable activities during whole pasteurization experiment at selected experimental conditions (70 °C, 40 min).