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Xanthan is a microbial biopolymer with a wide range of industrial applications and it is expected that the demand for this product will significantly increase in the coming decade and for this reason it is important to constantly work on improving all aspects of this biotechnological process. The aim of this research was to examine the kinetics of batch cultivation of Xanthomonas campestris ATCC 13951 using vegetable oil industry wastewaters as a basis for the cultivation medium, in order to produce the biopolymer xanthan. Kinetic modelling is very important for process control, reducing process costs and increasing product quality. By performing xanthan production on a medium with optimized content, the experimental values of content of biomass, carbon source and the desired product were obtained and used to determine the kinetics of biosynthesis. In order to describe biomass multiplication, product formation and carbon source consumption, the logistics, the Luedeking-Piret and modified Luedeking- -Piret equation, respectively, were successfully used. Additionally, using process simulation software (SuperPro Designer®), a process and cost model for a xanthan production facility was developed. The developed model represents the basis for a 21,294.29 and 23,107.97 kg/year xanthan production facility, which uses a vegetable oil industry wastewater-based medium and a semi-synthetic medium. The simulation model of the suggested xanthan production process, developed and based on defined kinetic models, represents an excellent basis for its further improvement and for increasing its efficiency. [ABSTRACT FROM AUTHOR]

In this research a process and cost model for a xanthan production facility was developed using process simulation software (SuperPro Designer ® ). This work represents a novelty in the field for two reasons. One is that xanthan gum has been produced from several wastes but never from wastewaters from confectionery industries. The other more important is that the aforementioned software, which in intended exclusively for bioprocesses, is used for generating a base case, i.e. starting point for transferring the technology to industrial scales. Previously acquired experimental knowledge about using confectionery wastewaters from five different factories as substitutes for commercially used cultivation medium have been incorporated into the process model in order to obtain an economic viability of implementing such substrates. A lower initial sugar content in the medium based on wastewater (28.41 g/L) compared to the synthetic medium (30.00 g/L) gave a lower xanthan content at the end of cultivation (23.98 and 26.27 g/L, respectively). Although this resulted in somewhat poorer economic parameters, they were still in the range of being an investment of interest. Also the possibility of utilizing a cheap resource (waste) and reducing pollution that would result from its disposal has a positive effect on the environment. [ABSTRACT FROM AUTHOR]

The aim of this research was to examine the possibility of using the vegetable oil industry wastewater as the basis of the cultivation media for xanthan production, using Xanthomonas campestris ATCC 13951, in order to reuse the wastewater obtained in one industry as a raw material in another. Furthermore, the aim was to optimize the composition of wastewater based media in terms of carbon, nitrogen, and phosphorus content. Experiments were carried out in accordance with the Box-Behnken design with three factors on three levels (glucose: 10.00--30.00 g/L; nitrogen: 0.02-0.20 g/L; phosphorus: 0.0045-0.045 g/L) and three repetitions at the central point. The success of biosynthesis was assessed by analysing broths to determine xanthan yield, cultivation broth apparent viscosity, residual carbon, nitrogen, and phosphorus content. Graphical and numerical optimization using response surface methodology was performed to determine the optimal content values of the carbon source, nitrogen, and phosphorus content. The results of graphical optimization suggest that for the defined response interval values, the defined model predicts that the xanthan production is possible when 15.00-16.00 g/L of the carbon source, 0.02-0.09 g/L of nitrogen and 0.01-0.02 g/L of phosphorus are added to the media that as a basis contains vegetable oil industry wastewater. [ABSTRACT FROM AUTHOR]

Abstract: This study examines the kinetics of a batch fermentation process of raw juice, an intermediate product of sugar beet processing, by free Saccharomyces cerevisiae yeast cells, with the aim of producing bioethanol. Defining the kinetics and kinetic parameters of this bioprocess may be regarded as an important step towards translating it to industrial scales (scale-up). The optimal values of the kinetic parameters were determined by fitting the models into the experimental data, i.e. by minimising the discrepancy between the model predictions and corresponding experimental data. The growth of yeast cells could be expressed by a logistic function model, which describes the growth as a function of initial biomass concentration, fermentation time, specific growth rate and final biomass concentration. The modified Gompertz model, which gives the bioethanol production lag time, the maximum bioethanol production rate and the maximum bioethanol concentration, was able to describe the formation of bioethanol as the fermentation proceeded. These models thus can be employed for further development of the bioethanol production process from sugar beet raw juice. [Copyright &y& Elsevier]

Abstract: The batch fermentation process of sugar beet processing intermediates by free yeast cells is the most widely used method in the Autonomous Province of Vojvodina for producing ethanol as fuel. In this study a process and cost model was developed for producing ethanol from raw juice. The model can be used to calculate capital investment costs, unit production costs and operating costs for a plant producing 44millionl of 99.6% pure ethanol annually. In the sensitivity analysis the influence of sugar beet and yeast price, as well as the influence of recycled biomass on process economics, ethanol production costs and project feasibility was examined. The results of this study clearly demonstrate that the raw material costs have a significant influence on the expenses for producing ethanol. Also, the optimal percentage of recycled biomass turned out to be in the range from 50% to 70%. [Copyright &y& Elsevier]

Abstract: In this study, the policy, market conditions and food security of biomass energy sources are assessed for supplying the future needs of Vojvodina. The Autonomous Province of Vojvodina is an autonomous province in Serbia, containing about 27% of its total population according to the 2002 Census. It is located in the northern part of the country, in the Pannonia plain, in southeastern Europe. Vojvodina is an energy-deficient province. The incentives to invest human and financial resources in the research and development of cleaner bioprocesses are high, considering the benefits which might be achieved in terms of environment protection and manufacturing costs. In the near and medium tenu, the development of bioprocesses for waste recycling and resource recovery might be one of the most viable options, considering much research work has already been done. In Vojvodina, there are technological solutions that biofuels produced in a closed cycle, so that the quantity of waste reduced to a minimum. These solutions include the stillage (remainder after distillation) used for fattening cattle, and cattle excrement to produce biogas and manure as fertilizer. The energy required for the production of bioethanol is obtained combustion lignocelullose residual waste from the production of basic raw materials starch, or biogas. Ash from the burned biomass returned to soil as a source of minerals for plants and replacement of mineral fertilizer. Such a closed cycle is economical for small farms in Vojvodina. [Copyright &y& Elsevier]

Abstract: The Autonomous Province of Vojvodina is an autonomous province in Serbia, containing about 27% of its total population according to the 2002 Census. It is located in the northern part of the country, in the Pannonia plain. The importance of sector of the environment protection becomes even larger and observable, especially with respect of the strategic determination of Government of the AP of Vojvodina, the Republic of Serbia on the association with the European economic area (EEA) and joining with the states – members of the European Union (EU). Restitution of the concept of the cleaner production (CP) significantly helps to companies and the responsible persons (especially in the domain of industry) to harmonize their business activities with law demands concerning the environment protection, as well as to improve their processes and the process sequences. This makes a starting base for the obtaining of the integrated license for the installations that are included in a list of installations that have to obtain an integrated licenses (some 250 installations), on the basis of the Law on the integrated prevention and control of pollution of Vojvodina, the Republic of Serbia, for which the dead point is the year 2015. [Copyright &y& Elsevier]

Serbia is a country located at the crossroads of Central and Southeastern Europe, covering the southern part of the Pannonian Plain and the central Balkans. After eight years of strong economic growth (average of 4.45% per year), the economy of the country has been affected by the global economic crisis and Serbia entered the recession in 2009 with a negative growth of −3% and again in 2012 with −1.7%. Reserves of oil and gas are limited so the country is heavily dependent on the import of oil. The country׳s economy has been under serious strain and the balance of the country׳s budget has been deteriorating due to the oil import bill. Environmental pollution, the import of fossil fuels as well as the ever-growing demand for energy are the reasons why investments and developments of renewable energy source technologies, as well as waste management procedures are crucial. Since Serbia is in the process of joining the European Union, it is extremely important to develop an adequate system of waste management together with the development of society and economy as a whole. The waste-to-energy process is environmentally, economically and socially sustainable and has strong potential to produce energy from communal and industrial waste, which are currently unused resources. In addition, it is necessary to integrate waste management procedures with waste quantity reduction. In this study, an attempt has been made to give suggestions for better utilization of municipal solid waste in Serbia through comprehensive reviews of commonly used municipal waste practices as well as data on waste generation, types and the amounts of communal and industrial waste. By exploiting the energy potential of municipal solid waste the country can ensure sustainable development as well as energy security. [ABSTRACT FROM AUTHOR]

The pollution caused by the use of fossil fuels for the production of mechanical or electrical energy is one of the most important environmental issues nowadays. In this respect, biofuels represent a viable source of energy. Bioethanol as a renewable energy source is derived from organic material of plant origin, so-called biomass, thus reducing environmental pollution. The aim of this study was to analyze the potential of bioethanol in meeting future energy demands in the Republic of Serbia. [ABSTRACT FROM AUTHOR]

Numerous species of the genus Streptomyces, on the appropriate cultivation medium in the process of submerged biosynthesis, as a product of the secondary metabolism, and under aerobic conditions synthesize pharmacologically active compounds. The aim of presented study was optimization of different nitrogen sources in the cultivation medium for the production of antimycotics using a strain of Streptomyces spp. isolated from the environment. Experiments were carried out in accordance with Box-Behnken design with three factors at three levels (peptone: 3.0 g/l, 7.0 g/l and 11.0 g/l; yeast extract: 1.0 g/l, 3.0 g/l and 5.0 g/l; soybean meal: 5.0 g/l, 15.0 g/l and 25.0 g/l) and three repetitions in the central point. Cultivation mediums were analyzed for determination of residual sugar, residual nitrogen, pellet diameter and RNA. Also, antimycotic activity of the obtained cultivation mediums was determined using diffusion disc method on the Aspergillus spp. as the test microorganism. For the optimization of selected parameters, a Response Surface Methodology was used and the obtained data were analyzed using the software package DESIGN EXPERT 8.1. Achieved model with a coefficient of determination (R) of 0.952 predicted that the maximum inhibition zone diameter (24.0 mm) against microorganism Aspergillus spp. and the minimum amount of residual sugar (0.551528 g/l) under applied experimental conditions was produced when the contents of varied nitrogen sources were: peptone 11.0 g/l, yeast extract 4.32 g/l and soybean meal 25.00 g/l. [ABSTRACT FROM AUTHOR]

Abstract: Due to the reduction of the economic support for refined sugar efforts have been made to find new ways of using sugar beet outside food industry. This paper investigates the possibilities of introducing bioethanol co-production in Serbian sugar plants. Research shows current state of Serbian sugar industry and technical aspects of bioethanol co-production in sugar plants. These results represent important step toward mass production of bioethanol in Serbian factories. The main goals of introducing the concept of sugar and bioethanol coproduction would be efficient use of available resources for the production of energy, reduction of greenhouse gases emission, decreased dependence on import and creation of new jobs. Besides that, it would provide flexibility in terms of variation of produced quantities of sugar and ethanol, depending on the conditions prevailing on the market. [Copyright &y& Elsevier]