0000000000308263
AUTHOR
E. Kaminska
The effect of chemical treatment of stainless steel wire surfaces onZymomonas mobilis cell attachment and product synthesis
The attachment, growth and product synthesis of non-flocculating Zymomonas mobilis cells, fixed in stainless steel wire spheres (WS), were investigated. The carrier surface was activated by treatment with titanium (IV) chloride (TiCl 4 ) and γ-aminopropyltriethoxysilane (AS) in an attempt to raise the efficiency in the immobilization of the cells. System productivity for ethanol and levan production, using cells immobilized on a modified stainless steel surface in the batch fermentation of a sucrose medium, rose as a result of increased biomass compared to the productivity of cells fixed on untreated (control) metal surfaces. Stabilized ethanol synthesis was demonstrated in the course of fo…
Fructan Biosynthesis by Intra- and Extracellular Zymomonas mobilis Levansucrase after Simultaneous Production of Ethanol and Levan
Summary The chemical composition of the Zymomonas mobilis biomass and the culture liquid after ethanol and levan synthesis were studied. The activities of intra- and extracellular levansucrase produced by the Z. mobilis strain 113 ”S” under optimum conditions both for levan and fructooligosaccharide (FOS) synthesis were also determined. It was shown that levan production relates to the reduction of the carbohydrate and lipid content in the biomass by increasing the nucleic acid and protein content. The levan producing activity of cellular levansucrase after ethanol and levan synthesis was approximately 30–40% of the total activity in the second fermentation stage. It was established that th…
Stillage as a Source of Growth Promoting Biofactors and a Stimulator of Levan and Extracellular Levansucrase Synthesis for Zymomonas mobilis
In the present work, the fermentation of simultaneous production of ethanol and levan by Zymomonas mobilis grown on different growth media has been studied. Yeast extract, rye stillage or sugar beet molasses stillage were used as additives to the basic sucrose media and the chemical composition, including vitamins, of the cultivation liquids have been determined. It has been shown that 0.5 % of yeast extract dry weight additive could be substituted by 10.0 % of native stillage additive. It was established that molasses stillage stimulates the ethanol synthesis, but rye stillage additive is more preferable for levan production. The extracellular levansucrase obtained from the culture liquid …
IR-spectroscopic studies of Zymomonas mobilis and levan precipitate
Abstract The mid-infrared (mid-IR) absorption spectra of Zymomonas mobilis 113 “S” bacterial biomass grown in sucrose or glucose medium, and levan precipitate in the fingerprint region were studied. IR-qualitative and quantitative analyses were carried out. The principal component concentration changes in Z. mobilis biomass at different growth phases showed that protein concentration was higher in case of glucose-based medium, but the total carbohydrate concentration was higher if grown in sucrose-based medium. Low concentration of intracellular carbohydrates was a characteristic parameter of levan-producing Z. mobilis cells. It was shown that during 2-month storage of Z. mobilis inoculum i…
Levan-ethanol biosynthesis using Zymomonas mobilis cells immobilized by attachment and entrapment
Fermentation of sucrose by Zymomonas mobilis cells attached to stainless steel wire spheres (WS) and to Al2O3 granules was compared with sucrose fermentation by cells entrapped in Ca-alginate. Similar amounts of cell biomass were applied at the beginning of the immobilized fermentation systems. The immobilization of Z. mobilis cells to the carrier surface was checked by scanning electron microscopy (SEM). Most cells were present in holes and pores of Al2O3 surfaces following colonization. Observation of the carrier after repeated fermentation cycles showed that a surface of Al2O3 granules was partly covered by levan. Alginate beads were extended in volume and partly disrupted. Changing the …
Attachment of yeast to modified stainless steel wire spheres, growth of cells and ethanol production
Abstract The immobilization of yeast Saccharomyces cerevisiae, their growth and ethanol production were investigated using untreated and modified stainless steel wire spheres (WS) as carriers. The carrier surface was modified by oxidation, by treatment with titanium (IV) chloride (TiCl4) or by γ-aminopropyltrietoxysilane (AS) in an attempt to raise the efficiency of the immobilization of the yeast cells. The influence of the cell fixation method on culture growth and ethanol synthesis was investigated. The immobilization of cells to carrier surface was checked by scanning electron microscopy (SEM). More closely attachment of yeast cells was seen on the aminated wire surface. It was establis…
Flame-burned stainless steel wire spheres as carriers ofZymomonas mobilis cells and extracellular levansucrase
In the present work, the use of flame-burned WS as carriers of Z. mobilis and extracellular levansucrase and the effect of the cell fixation method by dehydration on system productivity were investigated. Lyophilization and convective drying of Z. mobilis biomass at 30°C to a moisture content of 10–14% gave the best results for the repeated batch fermentations of a sucrose medium to obtain levan and ethanol. Significant correlation between the product formation and the concentration of free cells in the fermentation medium was established. Clearly, the cells were weakly bound to the newly generated WS and were washed out into the medium during fermentation. Here the hypothesis is presented …
Carbohydrates in Jerusalem artichoke powder suspension
Purpose – The aim of this study was to evaluate the influence of temperature and action time on the extraction rate of carbohydrates of Jerusalem artichoke concentrate powder and inactivation of inulin during boiling and sterilization.Design/methodology/approach – Water suspension of Jerusalem artichoke concentrate (5g/100ml) at 25, 50 and 100○C was tested after 5, 15, 30 and 60min to determine the content of inulin, glucose, fructose and sucrose and evaluate the extraction rate. The stability of inulin was studied after boiling and sterilization at 120○C during 1, 2 and 3h. The extraction rate was evaluated by Fourier‐Transform Infrared (FT‐IR) spectroscopy as well.Findings – It was shown …
Levan production byZymomonas mobilis cells. Attached to plaited spheres
In this work, an immobilization method for polymer-levan production by a non-flocculating Z mobilis culture was developed. The extent of cell attachment to the stainless steel wire surface, culture growth and product synthesis were described. It was established that during short-term passive immobilization of non-flocculating Z mobilis cells on a stainless steel wire surface, sufficient amounts of biomass for proper levan and ethanol fermentation could not be obtained. Adherence of cells was improved by pressing the paste-like biomass within stainless steel spheres knitted from wire with subsequent dehydration. Biomass fixed in metal spheres was used for repeated batch fermentation of levan…
Stability of levan produced by Zymomonas mobilis
Abstract The stability of levan produced by Zymomonas mobilis 113 “S” was investigated during storage of culture liquid at different pH and temperatures. Levan was not degraded if stored in a culture liquid for 120 h at 30 or 25 °C, but at 55 or 60 °C the degree of degradation was inversely proportional to pH. Cell biomass and levan sediment components did not cause the degradation of levan. The influence of organic acids (lactic-, acetic-, and gluconic) and HCl as levan hydrolyzing agents at pH 3.7, temperature 30 °C or 55 °C was investigated in a model solution. The hydrolytic effect was similar in the case of organic acids—ensuring more fructose formation, while HCl ensured higher amount…
Sugar Beet Juice Fermentation byZymomonas mobilis Attached to Stainless Steel Wire Spheres
The fermentation of sugar beet juice as well as juice syrup medium by Zymomonas mobilis inoculum attached to stainless steel wire spheres was investigated. A semi-synthetic sucrose medium enriched with mineral salts and yeast extract was used as the control. It was established that raw sugar beet juice ensured good Zymomonas mobilis culture growth and slightly decreased ethanol synthesis applying both flame-burned and TiCl 4 -treated wire spheres as carriers (Q x = 0.05-0.06 g/l × h: Q eth = 1.02-1.22 g/l × h). High ethanol yield was also observed in juice medium (Y = 0.45-0.46 g/g), however, levan synthesis with this medium decreased. The application of juice syrup brought about less growt…
Fermentation of Jerusalem artichoke by Zymomonas and Saccharomyces
PurposeThe aim of this study is to find out the appropriate fermentation conditions of Jerusalem artichoke powder (JAP) based media to obtain light beverage containing inulin.Design/methodology/approachJAP water suspension or filtrate were used for preparation of growth media with or without enzymatic hydrolysis of inulin for fermentation by Zymomonas mobilis 113 “S” or Saccharomyces cerevisiae.FindingsIf enzymatic hydrolysis of inulin was not used significantly higher amount of inulin (7.42 per cent) was unconverted by Z. mobilis than by S. cerevisiae (2.22 per cent) while the ethanol concentration was much higher (2.86 per cent) after S. cerevisiae fermentation than after Z. mobilis ferme…
Fructooligosaccharide and levan producing activity of Zymomonas mobilis extracellular levansucrase
Abstract The present work was devoted to investigations of the fructooligosaccharide (FOS) and levan forming activity of ethanol producing bacteria Zymomonas mobilis and their extracellular levansucrase. After cell separation the culture liquid was treated with ethanol to precipitate levan together with extracellular levansucrase. Levan–levansucrase sediment can be used as biocatalyst for fructooligosaccharide (FOS) production in sucrose syrup and levan sediment as soluble fibre source. The dynamics of sucrose conversion and glucose, fructose, and FOS formation by extracellular levansucrase showed that the fructose content increased only during the first 6 h, while the glucose content conti…