Production and characterization of rhamnolipid biosurfactant obtained by strain Pseudomonas aeruginosa san ai was investigated. With regard to carbon and nitrogen source several media were tested to enhance production of rhamnolipids. Phosphate-limited proteose peptone-ammonium salt (PPAS) medium supplemented with sun flower oil as a source of carbon and mineral ammonium chloride and peptone as a nitrogen source greatly improved rhamnolipid production, from 0.15 on basic PPAS (C/N ratio 4.0), to 3 g L-1, on optimized PPAS medium (C/N ratio 7.7). Response surface methodology analysis was used for testing effect of three factors: temperature, concentration of carbon and nitrogen source (w/w), in optimized PPAS medium on rhamnolipid production. Isolated rhamnolipids were characterized by IR and ESI-MS. IR spectra confirmed that isolated compound corresponds to rhamnolipid structure, whereas MS indicated that isolated preparation is a mixture of mono-rhamno-mono-lipidic, mono-rhamno-di-lipidic- and dirhamno- di-lipidic congeners

The rhamnolipids will most likely be the next generation of biosurfactants to reach the market. They should follow closely after alkyl polyglycosides, already established in the biosurfactants market, and sophorolipids, which can be found in several cleaning agents. However, the greatest numbers of recent publications and patents among glycolipid biosurfactants have been dedicated to rhamnolipids. Produced mainly by Pseudomonas aeruginosa, rhamnolipids are mixtures of different rhamnolipid congeners, which show physico-chemical properties that differ from those of single congeners, with the most abundant structure in the mixture having the largest impact on the overall characteristics of the total mixture. Characteristics of biodegradability, low toxicity, production from renewable sources and antimicrobial (particularly antifungal) activity together make rhamnolipid biosurfactants particularly promising for broad commercial application. Although to date, bioremediation has been the major topic filed for patents utilizing rhamnolipids, the increasing number of patents for applications in cosmetics, agronomy and food industries, formulation of cleaners and nanotechnology indicates their future implementation in these fields.

This paper analyzes the performance of the labour market in the predominantly rural areas of Serbia classified according to the OECD criterion of rurality (<150 inhabitants/km²). The research covers 18 NUTS III areas. The analysis emphasizes the structural problems of the aging population, poor education and unfavourable employment structure in the study area. A survey specifically refers to the consideration of demographic labour market index, directing the public policy actions toward different treatment of different rural areas in Serbia. The specific answer is found in the new approach based on innovativeness and the model of creative rural industrialization

The energy market is characterized by significant imperfections. Negative external effects and other market imperfections have, among other things, a serious consequence - they send the wrong price signals and mask the real costs that arise in the process of energy production and consumption. As a result, there is a serious degradation of the environment at the local and global level. Negative effects at the global level, such as the depletion of non-renewable resources and changes in the global climate, represent the most serious challenges facing humanity today. Public sector responses to market imperfections, in the form of various measures and instruments, are well known in economic theory and have proved effective in practice in many circumstances. However, the fact that giving priority to economic and social goals in public policies can have and often results in deterioration of the quality of the environment is mainly ignored in the professional literature even today. In addition, the failure of energy regulations leads to environmental degradation. The situation is especially critical in many developing countries. In the race to achieve goals in the field of industry, agriculture or energy, there are major environmental problems that lead to environmental unsustainability as collateral damage. From an economic point of view, both the effectiveness and efficiency of energy policy are important, in terms of its potential to contribute to improvements in the field of environmental protection and energy efficiency. One of the best strategies is to introduce important aspects of the environment into the market sphere. In this way, the limitations of natural resources would be reflected in their prices. Abolishing the practice of large subsidies and underestimation of fossil fuel prices is certainly a step in the right direction.

The paper starts from the concept of the Open Balkan as a community of countries in the Western Balkans, aimed at strengthening their economic cooperation and development for faster integration in the European Union. Significant attention is paid to the analysis of the interdependence of (in)stability of the state and the economic development of small countries. The position of the Open Balkan and its members is also analysed on the basis of the selected global composite indices. An important subject of the analysis is also the condition of institutional capacities of the members of the Open Balkan and their institutional cooperation from the perspective of faster progress towards the European integration. Two main hypotheses have been tested in the paper: (H1) CEEs countries are not a homogeneous group of countries; and (H2) The Western Balkans is a relatively homogeneous regional integration. To test the convergence hypothesis between 16 Central and Eastern European countries (CEEs), annual data from World Bank’s database on the value of real gross domestic product per capita (in constant dollars 2017, PPP) in the period 2000-2026 were used (projected values for the period until 2026). We employed the method developed by Phillips & Sul (2007) that allows identification of clusters of convergence on the basis of an algorithm that is data-driven and thereby avoids a priori classification of the data into subgroups. Based on the results obtained, it can be concluded that Serbia is the “locomotive” of the Western Balkans and that all countries in this area should join the regional initiative for cooperation, the Open Balkan.