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Wine industry generates large volumes of wastewaters resulting from numerous cleaning operations that occur during the different stages of winemaking. Disposal of these effluents in the environment causes huge problems due to their high organic and inorganic load and seasonal variability. The bioconversion of winery wastewaters in valuable product, such as xanthan, is an important alternative to overcome environmental problems. In this research, the possibility of xanthan production using Xanthomonas campestris on blended wastewaters from different stages of white and rose wine production with initial sugar content of 50 g/L was investigated. In addition to the media parameters (content of sugars, total and assimilable nitrogen, phosphorus, total dissolved salts and apparent viscosity), raw xanthan yield and degree of sugar conversion into product were determined in order to examine the success of xanthan biosynthesis. In applied experimental conditions, xanthan yield of 20.92 and 30.64 g/L and sugar conversion into product of 40.23 and 60.73% were achieved on wastewaters from white and rose wine production, respectively. The results of these experiments suggest that winery wastewaters, after additional optimization of the process in terms of the substrate composition and the cultivation conditions, may be a suitable raw material for industrial xanthan production.

Article Highlights• A novel aerobic denitrifier, P. stutzeri D1 was isolated • P. stutzeri D1 has great capability to fully reduce 3g/L of nitrate in aerobic conditions• The optimal conditions for biomass scale-up was determined• The scale-up of biomass production of P. stutzeri ATCC 17588 and D1 strain was performed Abstract An aerobic denitrifier was newly isolated and identified by VITEK ® 2 Compact System and MALDI-TOF MS as P. stutzeri strain D1. Sequence amplification indicates that the denitrification genes napA, nirS, norB and nosZ are present in a novel strain D1, as well as in reference strain ATCC 17588. Strain D1 had capability to fully remove 3 g/L of nitrate (as KNO 3 ) in 48 h, while the reference strain completed this task in 60 h. Single factor experiments indicate that the optimal conditions for biomass production were: temperature of 30 °C, pH value of 7 and inoculum volume of 5 vol.%. Scaling up of biomass production of both denitrifiers was successfully performed in 3 and 7 L laboratory bioreactors by reaching 9 log CFU/mL of the viable cells. The results demonstrate the feasibility of using investigated P. stutzeri strains in denitrification processes and the simplicity of the up-scaling of biomass production for the treatment of large areas contaminated with nitrate.