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…

Stabilization of anti-leukemic enzyme l-asparaginase by immobilization on polysaccharide levan

Abstract Biologically active fructose polymer levan from Zymomonas mobilis of different molecular mass (75 and 2000 kDa) was covalently coupled to anti-leukemic enzyme Erwinia carotovora l -asparaginase. The method used for the immobilization of the enzyme involved periodate oxidation of the polysaccharide, followed by reductive alkylation. A gentle periodate oxidation of levan (oxidation degree ≤24%) resulted in the highest residual enzyme activity (≥55%). The K m(app.) of glycoconjugates was higher than the K m of native l -asparaginase. The conjugation of l -asparaginase widened the optimum pH range of the enzyme. The electrophoretic mobility in polyacrylamide gel of glycoconjugates obta…

A novel and simple method for the purification of extracellular levansucrase from Zymomonas mobilis.

A new and simple method for the purification of extracellular levansucrase from Zymomonas mobilis from highly viscous fermentation broth was developed. After incubation of the fermentation broth with a fructose-polymer cleaving enzyme preparation (Fructozyme, Novozymes, DK) for 48 h, levansucrase precipitated as aggregates and was redissolved in a 3 M urea solution. By ongoing size-exclusion chromatography on Sephacryl S-300 the final levansucrase preparation was purified 100-fold and exhibited a specific activity of 25-35 U/mg(protein). The levansucrase was stable in 3 M urea solution for at least four months without inactivation. To maximize the enzyme yield the dynamic changes of extrace…

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…

OATS AND FAT-FREE MILK BASED FUNCTIONAL FOOD PRODUCT

The present study addresses problems and solutions related to new functional bio-active food product creation. Commercial rolled oats and fat-free milk were used as raw materials. Limited enzymatic hydrolysis of oat starch was carried out by α-amylase. The lactic acid bacteria strains Lactobacillus acidophilus, Bifidobacterium sp., and commercial starter cultures ABT-1 were cultivated in enzymatically hydrolysed oat mash. Lactobacillus acidophilus was a more active producer of lactic acid, while Bifidobacterium sp. improved the taste properties. A fat-free milk additive was applied to stabilise the texture of the oat mash, and increase the protein content of the final product. All procedure…

Influence of some physicochemical factors on the viscosity of aqueous levan solutions ofZymomonas mobilis

Zymomonas mobilis strain 113 “S” produces levan – an extracellular, viscous, biologically active, non-toxic fructose polymer with a unique structure and extraordinary properties. This polysaccharide was isolated at two different degrees of purity by alcohol precipitation from aqueous solutions and was characterized with respect to some rheological properties and stability of viscous solutions. The effects of temperature, pH and salt concentration on the viscosity of 1–3% levan solutions were examined. The viscosity of levan solutions was found to be quite stable and reversible at room temperature over a wide range of pH from 4 to 11. The viscosity was slightly affected by increased salt con…

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 …

The effect of osmo-induced stress on product formation by Zymomonas mobilis on sucrose

The intensification of biosynthesis of fructooligosaccharides in the presence of high salt concentrations was observed during sucrose (10%) fermentation by Zymomonas mobilis 113S. A 0.6 M NaCl concentration led to an increase of oligosaccharide productivity by 3.5-fold. Sorbitol formation was increased in the presence of 0.16 M NaCl and was inhibited at highest salt concentrations. In a medium with high (65%, w/w) sucrose content the salts gave inhibitory effects on fructooligosaccharide production by lyophilised Z. mobilis cells. Influence of salts on gluconic acid and sorbitol formation under these conditions was studied. The ratio of oligosaccharides and gluconic acid productivity (Qolig…

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…

Sucrose medium osmolality as a regulator of anabolic and catabolic parameters inZymomonas culture

This study focuses on the growth of Zymomonas mobilis strain 113 S and its ethanol and levan production under the conditions of increasing sucrose medium osmolality caused by NaCl, KCl, sorbitol or maltose. The increase in medium osmolality (700-1,500 mosml/kg) was accompanied by the inhibition of growth (growth rate, biomass yield) and ethanol production (specific productivity and yield). In contrast, levan synthesis was less affected or even stimulated and, as a consequence, levan specific productivity was increased significantly. A decrease in the anabolic growth parameters correlated with a parallel inhibition of glucose-6-P dehydrogenase and alcohol dehydrogenase (isoenzyme ADH II) act…

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…

Fructan-Biosynthese durch in Membranen immobilisierte Levansucrase

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…

Quantitative analysis of oat by Infrared spectroscopy

Oat products as a source of soluble dietary fibre have shown to exhibit distinct hypocholesterolemic and hypoglycaemic effects in humans and recently have become a key focus of the nutrition and medical communities. Interest in assaying the contents of (1→3), (1→4)-β-D-ghican, referred to hereafter as β-glucan, in barley, malt and oat has been increasing because of its nutritional and technological importance [1].

Stabilization of immobilized cell systems using a modified metal surface, fructose polymer levan and a high cell concentration

An Influence of Fructan Containing Concentrate from Jerusalem Artichoke Tubers on the Development of Probiotic Dairy Starters on Milk and Oat-based Substrates

Supplementation of milk and oat hydrolysate containing medium with Jerusalem artichoke concentrate (JAC) and subsequent fermentation with probiotic dairy starters resulted in substantial stimulation of probiotics Bifidobacterium lactis and Lactobacillus acidophilus as well as yogurt starter culture Lactobacillus bulgaricus development and acidification rate. The strain-specific responses of the general yogurt cultures, as well as probiotics to the addition of JAC, should be considered to achieve optimal composition of probiotic strains and conformable fermentation conditions. JAC is suggested to be perspective prebiotic additive for fermented synbiotic milks or oat-hydrolysate-based product…

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…

A Closed Biotechnological System for the Manufacture of Nonfood Products from Cereals

The production of nonfood products from agricultural raw materials is an important challenge. Efficiency of grain processing for sustainable development depends to a large extent on the harmony of the proposed system. Such a system must include consideration of all steps in the cycle from preparation of the field through cultivation of the grain crop; harvesting; total biomass utilization during processing stages; treatment of wastes; and back to preparation of the field. A closed biotechnological system can be recommended for processing of agricultural raw materials. Ethanol production from potatoes in a closed system is presented in Figure 1. Lysine production is represented schematically…

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…

Development ofBifidobacterium lactis Bb 12 onβ-(2,6)-Linked Fructan-Containing Substrate

β-(2,1)-linked fructan of plant origin (inulin) and the related oligosaccharides (FOS) as non-digestible carbohydrates, i.e., potent prebiotics, can stimulate the growth of various probiotic lactic acid bacteria, including a number of bifidobacteria strains. The related (3-(2,6)-linked fructans of microbial origin (levan and FOS), however, have scarcely been investigated in this respect. Therefore, the bifidogenic properties of various fructans, i.e., inulin, levan, fructooligosaccharides (FOS) and fructan syrup (FS), were tested as glucose substitutes in MRS media and were compared concerning their effect on the commercial strain Bifidobacterium lactis Bb 12. Although glucose was the prefe…