Biological treatment of different food industrial wastewater by Xanthomonas campestris

Biological wastewater treatment is certainly one of the most important biotechnological processes, which have been used for over a century to treat municipal and industrial wastewaters. Industrial wastewater causes large-scale environmental problems mainly because of its extremely high organic content. Xanthan biosynthesis is usually performed on substrates containing different carbohydrates and nitrogen sources. These nutrients are often obtained from different raw materials that are intermediate or by-products of various food technologies. One of the greatest factors limiting the use of xanthan in large-scale fermentation processes is the cost of production when compared with similar polymers from algae or plants. The cost of feedstock used for polymer production is area where savings could be made in this respect. The present study examines xanthan production by Xanthomonas campestris under aerobic conditions on different food industrial wastewaters. Cultivation media were prepared to contain same amounts of carbon and nitrogen sources and all experiments were performed simultaneously, so that all stages of the biotechnological process would be carried out under identical conditions. In order to determine success of the performed biosynthesis, yield of xanthan and sugar conversion were determined. From this point of view, similar results were obtained. Also, different viscosities of cultivation media at the end of process were compared. Determined significant differences of viscosities and at the same time similar yield of xanthan suggest that biosynthesized polymers have different quality. High values of sugar and nitrogen conversions advocate that significant decrease of organic content in applied industrial wastewaters

Potential of Xanthomonas strains isolated in Serbia for Xanthan production from crude glycerol

Xanthan is a natural polysaccharide that is biosynthesized by metabolic activity of Gramnegative bacteria from the genus Xanthomonas. Commercial production of xanthan is mainly performed as aerobic submerged batch cultivation of the reference strain X. campestris ATCC 13951 on a medium of appropriate composition and under optimal conditions. The success of xanthan production is largely influenced by the selection of producing strains, formulation of cultivation medium composition, and control and regulation of bioprocess parameters. The aim of this study was to examine xanthan production on medium containing crude glycerol from domestic biodiesel industry using reference strain Xanthomonas campestris ATCC 13951 and Xanthomonas strains locally isolated from different vegetable cultures. Xanthan was produced by submerged cultivation of examined producing strains at a laboratory level under aerobic conditions at 30°C and 150 rpm for 168 h. Bioprocess efficacy was estimated based on the xanthan concentration in media at the end of biosynthesis. According to the obtained results, xanthan production on crude-glycerol based medium was possible by all applied Xanthomonas strains. The highest potential for successful xanthan production has PL4 strain, while strain Xp 3-1 has the lowest ability to biosynthesize xanthan in applied experimental conditions

Proizvodnja bioetanola iz ekstrahiranog soka kao međuproizvoda prerade šećerne repe: primjena metode odzivne površine

Response surface methodology (RSM) was used for selecting optimal fermentation time and initial sugar mass fraction in cultivation media based on raw juice from sugar beet in order to produce ethanol. Optimal fermentation time and initial sugar mass fraction for ethanol production in batch fermentation by free Saccharomyces cerevisiae cells under anaerobic conditions at the temperature of 30 °C and agitation rate of 200 rpm were estimated to be 38 h and 12.30 % by mass, respectively. For selecting optimal conditions for industrial application, further techno-economic analysis should be performed by using the obtained mathematical representation of the process (second degree polynomial model). The overall fermentation productivity of five different types of yeast was examined and there is no significant statistical difference between them.Metodom odzivne površine optimirano je vrijeme fermentacije i maseni udjel šećera u hranjivoj podlozi za proizvodnju etanola u kojoj je glavni sastojak sok ekstrahiran iz šećerne repe. Optimalno je vrijeme fermentacije 38 h i početni maseni udjel šećera od 12,30 % u proizvodnji etanola šaržnim uzgojem slobodnih stanica Saccharomyces cerevisiae u anaerobnim uvjetima pri temperaturi od 30 ºC i brzini miješanja od 200 o/min. Da bi se odredili optimalni uvjeti fermentacije u industrijskom mjerilu, potrebno je provesti daljnju tehnološko-ekonomsku analizu primjenom dobivenog matematičkog modela (polinom drugoga reda). Ispitana je produktivnost pet različitih tipova kvasaca i među njima nije utvrđena statistički značajna razlika

Definition of initial phosphorus source concentration in waste glycerol-based medium for xanthan biosynthesis

Phosphorus nutrition appears to be very important in the xanthan production, next to carbon and nitrogen. Various studies indicated that xanthan production is controlled by phosphorus concentration in cultivation medium and that phosphorus is generally added in the form of phosphate salts. This paper presents an analysis of the effect of various K2HPO4 concentrations (0-3.00 g/L) in waste glycerol-based medium on xanthan production using Xanthomonas strain PL 4 isolated from pepper leaves. The bioprocess success was assessed based on the values of xanthan concentration in media at the end of biosynthesis, average molecular weight of the polymer, degree of glycerol conversion into xanthan and degree of total phosphorus conversion. The obtained results show that the increase of K2HPO4 concentration in medium from 0 g/L to 2.50 g/L significantly contributes to the rise in xanthan amount and its molecular weight, while further increase of phosphorus source concentration has a statistically insignificant effect on the values of these parameters. The greatest bioprocess success is achieved when the concentration of K2HPO4 in medium was 2.50 g/L. Cultivation of producing strain on medium with optimal K2HPO4 concentration resulted in high production of xanthan (13.26±0.20 g/L) of good quality (3.38±0.14·105 g/moL) along with a relatively high degree of phosphorus conversion (73.62±0.02%)

Xanthan production on glycerol-based media : a mini review

Xanthan is the most important microbiological polysaccharide. This biopolymer has widespread commercial applications as a viscosity enhancer, emulsifier and stabilizer in the food, pharmaceutical and petrochemical industries. The yield and properties of the produced xanthan are largely dependent on the producing microorganism, medium composition and process parameters. In industrial conditions, a pure bacterial culture is used to produce xanthan on a medium containing glucose or sucrose as a carbon source. However, the increasing market price and demand for these sugars indicate the need for implementation of an alternative raw material. Hence, many studies are focused on finding cheap and available, alternative raw materials, rich in carbon sources, as a replacement for mentioned sugars. Results from several studies indicate that certain strains of bacteria of the genus Xanthomonas possess the ability to biosynthesize xanthan on a medium with glycerol as the sole carbon source. The aim of this study is to discuss data from available scientific literature related to the xanthan production on glycerol-based media

Effect of fermentation conditions on content of phenolic compounds in red wine

The evidence of compounds that increase the nutritive value of red wines has been presented in a number of papers. These compounds include catechins and proanthocyanidins among others. Their protective effect on the cardiovascular system and anticarcinogenic properties has been proved. The effect of maceration conditions and increased solid grape parts content, seed in the first place, on the content of phenolic compounds of wine was investigated. Several micro-trials were performed with Cabernet sauvignon sort; in some variants time and temperature of maceration were varied, while the ratio of residual stem and content of seed was increased several times, resulting in a significant change of phenolic compounds content in the obtained wine samples. The presence of ripe stem yielded good results, but only during six days of maceration, while in the case of longer maceration, the change of colour quality was negative. Supplementary quantities of seeds during maceration resulted in an increase of total phenols and catechins. A significant influence on colour of wines was also observed, especially in wines obtained applying shorter maceration

Biosynthesis of xanthan gum on wastewater from confectionary industry

Xanthan gum is one of the major commercial biopolymers employed in many industrial processes owing to its unique physical properties such as a high degree of pseudoplasticity and high viscosity even at low concentrations. Commercially available xanthan gum is relatively expensive due to glucose or sucrose being used as the sole carbon source for its production and cost reduction could be achieved by using less expensive substrates, such as food industrial wastewaters. Effluents from the confectionery industry, because of its high organic content, are significant environmental pollutants and before their release into environment it is necessary to purify them. The present study examines xanthan production by Xanthomonas campestris under aerobic conditions on wastewaters from five different factories of the confectionery industry. Xanthan yield was obtained as a quantitative characteristic of the process and was in the range between 4.28 g/L and 10.03 g/L and its quality is determined by following rheological characteristics of obtained cultivation media. The results obtained in this study indicate that wastewater from confectionary industry can be used as the basis of media for the production of this highly valuable product

Biosynthesis of xanthan gum on wastewater from confectionary industry

Xanthan gum is one of the major commercial biopolymers employed in many industrial processes owing to its unique physical properties such as a high degree of pseudoplasticity and high viscosity even at low concentrations. Commercially available xanthan gum is relatively expensive due to glucose or sucrose being used as the sole carbon source for its production and cost reduction could be achieved by using less expensive substrates, such as food industrial wastewaters. Effluents from the confectionery industry, because of its high organic content, are significant environmental pollutants and before their release into environment it is necessary to purify them. The present study examines xanthan production by Xanthomonas campestris under aerobic conditions on wastewaters from five different factories of the confectionery industry. Xanthan yield was obtained as a quantitative characteristic of the process and was in the range between 4.28 g/L and 10.03 g/L and its quality is determined by following rheological characteristics of obtained cultivation media. The results obtained in this study indicate that wastewater from confectionary industry can be used as the basis of media for the production of this highly valuable product

RHEOLOGICAL PROPERTIES AND THE ENERGETIC VALUE OF WHEAT FLOUR SUBSTITUTED BY DIFFERENT SHARES OF WHITE AND BROWN RICE FLOUR

In order to produce dough with a lower gluten content, more enriched with rice components and satisfactory rheological properties, the rheological properties, energetic value and cake baking properties of wheat and white or brown rice flour in shares from 3 to 30% (w/w) were investigated in this paper. The water absorption in wheat-rice flour mixtures was lower and decreased to 53.5% and 54.0% along with the increase of the white and the brown rice flour share, respectively, than in wheat flour, where it was 58.8%. In the dough made from rice flour, a gluten network had thinner filaments, about 2 and 1 μm in width for white and brown rice flour, respectively, compared to those in the dough from wheat flour only, where it was about 7 μm. The dough from rice flour had almost twice higher gelatinization maximum than the gelatinization maximum of the wheat flour only. The energetic values of the dough from rice flour were smaller than the energetic value of the wheat flour, for only 1.32%. Based on Cluster analysis, the white or brown rice flour share of 20% was pointed out