Novel fructooligosaccharide conversion from sugarcane syrup using a specialised enzymatic pH-stat bioreactor

Fructooligosaccharides (FOS) have gained significant attention for their prebiotic properties. Given that sugarcane syrup (SS) is sucrose-rich but with other nutritional benefits, its direct transformation into FOS may add value to this product. Therefore, the aims of this study were to develop FOS conversion from SS and to define the kinetic behaviour of FOS synthesized in a 1-L specialized pH-stat bioreactor (SPSB). The SS was composed of sucrose (58.93%) with considerable antioxidant capacities and Ƴ-aminobutyric acid. The developed SPSB process consisted of three stages: evaporation of sugarcane juice into syrup (68–75 °Brix) (stage 1), optimization of the Viscozyme L and SS mixture at different reaction temperatures (47–55 °C) (stage 2), and upscaling of the optimized reaction system under defined conditions in a 1 L-SPSB system (stage 3). In the 1 L-SPSB system, the enzymatic reaction yielded 32.22% of FOS from SS after a 6 h reaction, which is comparable with a pure system containing an equivalent concentration of 10% of sucrose as initial substrate with 39.55% yield. This result demonstrated the efficient conversion of SS into FOS, supporting the utilization of sugarcane juice for its health benefits.     

Fructo-oligosaccharides purification from a fermentative broth using an activated charcoal column

In this study, a simple and efficient process to purify fructo-oligosaccharides (FOS) from a fermentative broth was proposed using a single activated charcoal column. The FOS adsorption onto the activated charcoal was modeled by a pseudo-second order model. Several volumes and concentrations of water/ethanol were studied to optimize the selective desorption of sugars from the broth mixture at 25°C. Mixtures containing 50.6% (w/w) of FOS (FOS content in the fermentative broth) were purified to 92.9% (w/w) with a FOS recovery of 74.5% (w/w). Moreover, with the proposed process, fractions with purity up to 97% (w/w) of FOS were obtained. This purification process was also found to be efficient in the desalting of the fermentative broth.     

Physicochemical characterization of fructooligosaccharides and evaluation of their suitability as a potential sweetener for diabetics

Fructooligosaccharides (FOSs) were prepared from sucrose using fungal fructosyl transferase (FTase) obtained from Aspergillus oryzae MTCC 5154. The resulting mixture consisted of glucose (28-30%), sucrose (18-20%) and fructooligosaccharides (50-54%) as indicated by HPLC analysis. Identification of oligomers present in the mixture of fructooligosaccharides was carried out using NMR spectroscopy and LC-MS. No compounds other than mono-, di-, tri-, tetra- and pentasaccharides were identified in the FOS mixture prepared using FTase. NMR and LC-MS spectra proved the absence of any toxic microbial metabolites of Aspergillus species in FOS thereby emphasizing its safe use as a food ingredient. Animal studies conducted on streptozotocin-induced diabetic rats suggested that the use of FOS as an alternative non-nutrient sweetener is without any adverse effects on various diabetes-related metabolic parameters. Despite the high free-sugar content associated with it, FOS did not further aggravate the hyperglycemia and glucosuria in diabetic animals, even at 10% levels. On the other hand, by virtue of its soluble fibre effect, it has even alleviated diabetic-related metabolic complications to a certain degree.     

Structural analysis and optimised production of fructo- oligosaccharides by levansucrase from Acetobacter diazotrophicus SRT4

Major fructo-oligosaccharides (FOS) produced by levansucrase (EC 2.4.1.10) from Acetobacter diazotrophicus SRT4 were characterised as 1-kestose and nystose by acid hydrolysis and 13C-NMR spectroscopy. The highest yields of 1-kestose (481 mM; 241 g/l) and nystose (81 mM; 54 g/l) were achieved at initial sucrose concentration of 1754 mM (600 g/l), pH 5.5 and 40°C. The synthesized FOS reached 50% (w/w) of total sugars in the reaction mixture, with a conversion efficiency over 70% (w/w) based on the amount of sucrose converted to 1-kestose.     

Kinetics of Bifidobacterium longum ATCC 15707 fermentations: effect of the dilution rate and carbon source

The effect of the dilution rate on biomass and product synthesis in fermentations of glucose, fructose and a commercial mixture of fructooligosaccharides (FOS) by Bifidobacterium longum ATCC 15707 was studied. Kinetic parameters (maximum specific growth rate, Monod constant, maintenance, and yield coefficients) in the mathematical model of the fermentation were estimated from experimental data. In the FOS mixture fermentations, approximately 12% of the total reducing sugars (mainly fructose) in the feed were not metabolized by the bacterium. In fermentations of fructose and the FOS mixture, biomass concentration increased as the dilution rate increased and, once maximum values were reached [3.90 (D=0.20 h^–1) and 2.54 g l^–1 (D=0.15 h^–1), respectively], decreased rapidly as the culture was washed out. Formic acid was detected at low dilution rates in glucose and fructose fermentations. The main products in fermentations of the three carbon sources were lactic and acetic acids. Average values of the molar ratio between acetic and lactic acids of 1.18, 1.21 and 0.83 mol mol^–1 were obtained in glucose, fructose and FOS mixture fermentations, respectively. In batch fermentations carried out without pH control this molar ratio was lower than 1.5 only when fructose was used as the carbon source.     

Production of high fructo-oligosaccharide syrup with two enzyme system of fructosyltransferase and glucose oxidase

Summary A novel two enzyme system of fructosyltransferase and glucose oxidase to enhance the content of the net fructo—oligosaccharide (FOS) fractions in the industrial production of FOS syrup from sucrose was devised. The net FOS content in the commercial FOS syrup has been limited only to 55–60 % due to the accumulation of glucose which acts as a feedback inhibitor of the fructosyltransferase. By supplementing glucose oxidase to the conventional FOS reaction system, we could convert the glucose to gluconic acid readily separable from neutral sugars by simple ion exchange operation in the next step. The simultaneous removal of glucose was proved effective in proceeding the reaction by fructosyltransferase further by relieving the product inhibition caused by glucose. By this way, we could raise the net FOS content as high as 90 %.     

In vitro study on gas generation and prebiotic effects of some carbohydrates and their mixtures

This study was carried out to examine the effect of inulin (IN), fructooligosaccharide (FOS), polydextrose (POL) and isomaltooligosaccharides (ISO), alone and in combination, on gas production, gas composition and prebiotic effects. Static batch culture fermentation was performed with faecal samples from three healthy volunteers to study the volume and composition of gas generated and changes in bacterial populations. Four carbohydrates alone or mixed with one another (50:50) were examined. Prebiotic index (PI) was calculated and used to compare the prebiotic effect. The high amount of gas produced by IN was reduced by mixing it with FOS. No reduction in gas generation was observed when POL and ISO mixed with other substrates. It was found that the mixture of IN and FOS was effective in reducing the amount of gas produced while augmenting or maintaining their potential to support the growth of bifidobacteria in faecal batch culture as the highest PI was achieved with FOS alone and a mixture of FOS and IN. It was also found that high volume of gas was generated in presence of POL and ISO and they had lower prebiotic effect. The results of this study imply that a mixture of prebiotics could prove effective in reducing the amount of gas generated by the gut microflora.     

游离及固定化果糖基转移酶部分酶学性质的比较研究

 从诱变、筛选的米曲霉GX0 0 10菌株所产生的果糖基转移酶 ,经过纯化和固定化操作分别制备游离酶和固定化酶 ,对两者的酶学性质进行了比较研究 .结果表明 ,两者在蔗糖转化为蔗果低聚糖的酶促反应中 ,最适pH为 5 5,在pH5 0～ 7 5之间酶活性相对稳定 .游离酶和固定化酶的适宜温度范围分别是 4 5～ 52℃和 4 0～ 55℃ .在 55℃保温 60min ,酶活性保存率分别是 61 6%和 87 5% .固定化酶的热稳定性提高 .0 1mmol LHg2 +和 1mmol LAg+能完全抑制游离酶的活性 ,但只能部分抑制固定化酶的活性 ,1mmol L的Ti2 +能完全抑制两者的活性 .以蔗糖为底物时 ,游离酶的米氏常数Km=2 15mmol L ,而固定化酶Km =386mmol L .游离酶只能使用一次 ,固定化酶反复使用 54次后 ,剩余活力为 55 2 % .用 55% (W V)蔗糖溶液与固定化酶在pH5 0 ,4 6℃下作用 12h ,可获得61 5% (总低聚糖 总糖 )产物 ,其中蔗果五糖含量达到 7 2 % .     

Fructooligosaccharides consumption inhibits the loss of iron from the incisor enamel surface in gastrectomized rat

We examine the effects of fructooligosaccharides (FOS) on the reduction in the incisor iron content in gastrectomized rat. Twenty-eight 5-wk-old male Sprague-Dawley rats were divided into two groups: sham operated (bSH) and gastrectomized (bGX). After 4 wk each group was divided into two subgroups according to the presence or absence of 7.5% FOS in the synthetic diet (SH, SH+FOS, GX, and GX+FOS). At 10 wk wafter surgery, the maxilla was prepared to examine the iron content of the incisor enamel surface at four points. These points corresponded to the iron content at 6,7,8, and 10 wk, respectively. Blood was collected to determine serum iron levels at 4 and 10 wk. The serum iron level significantly decreased at 4 and 10 wk the GX group. At 10 wk, the level in the GX+FOS group significantly increased but did not reaach that in the SH group. The iron content of the enamel surface time-dependently increased and no significant differences were seen between SH and GX+FOS at 8 and 10 wk. These results suggest that FOS consumption impaired the loss of enamel content following gastrectomy, and this effect preceded the effect on the serum iron level.     

Biosynthesis of fructo-oligosaccharides by<Emphasis Type="Italic"> Sporotrichum thermophile</Emphasis> during submerged batch cultivation in high sucrose media

Biosynthesis of fructo-oligosaccharides (FOS) was observed during growth of the thermophilic fungus Sporotrichum thermophile on media containing high sucrose concentrations. Submerged batch cultivation with the optimum initial sucrose concentration of 250 g/l allowed the production of 12.5 g FOS/l. The FOS mixture obtained was composed of three sugars, which were isolated by size-exclusion chromatography. They were characterized by acid hydrolysis and HPLC as 1-kestose, 6-kestose and neokestose. The mechanism of osmotic adaptation of S. thermophile was investigated and sugars and amino acids were found to be the predominant compatible solutes. The fungus accumulated glutamic acid, arginine, alanine, leucine and lysine, in order to balance the outer osmotic pressure. Fatty acid analysis of the membrane lipids showed a relatively high percentage of unsaturated lipids, which is known to be associated with high membrane fluidity.     

Fermentations of fructo-oligosaccharides and their components by Bifidobacterium infantis ATCC 15697 on batch culture in semi-synthetic medium

AIMS: To compare the physiological behaviour of Bifidobacterium infantis ATCC 15697 growing on synthetic oligofructose or its components. METHODS AND RESULTS: The studies were carried out in regulated or non-regulated batch cultures on semi-synthetic media. Differences between the carbohydrate utilization patterns with glucose, fructose, sucrose and fructo-oligosaccharides (FOS) were determined. Glucose was the preferred substrate for growth and biomass production, whereas fructose was the best for lactate and acetate production. With sucrose, biomass production reached the level obtained with glucose, whereas with FOS, more metabolites were produced, as with fructose. In a mixture of FOS, the shorter saccharides were used first and fructose was released in the medium. Fructofuranosidase, an enzyme necessary to hydrolyse FOS, was inducible by fructose. CONCLUSION: Glucose contained in FOS and sucrose might sustain growth and cell production, while fructose might enable the production of major metabolites. SIGNIFICANCE AND IMPACT OF THE STUDY: A better understanding of the bifidogenic nature of oligofructose has been gained.     

Fosfomycin resistance: selection method for internal and extended deletions of the phosphoenolpyruvate:sugar phosphotransferase genes of Salmonella typhimurium.

Selection for resistance to the antibiotic fosfomycin (FOS; L-cis 1,2-epoxypropylphosphonic acid, a structural analogue of phosphoenolpyruvate) was used to isolate mutants carrying internal and extended deletions of varying lengths within the ptsHI operon of Salmonella typhimurium. Strains carrying "tight" ptsI point mutations and all mutants in which some or all of the ptsI gene was deleted were FOS resistant. In contrast, strains carrying ptsH point mutations were sensitive to FOS. Resistance to FOS appeared to result indirectly from catabolite repression of an FOS transport system, probably the sn-glycerol-3-phosphate transport system. Resistant ptsI mutants became sensitive to FOS when grown on D-glucose-6-phosphate, which induces an alternate transport system for FOS, or when grown in the presence of cyclic adenosine 3',5'-monophosphate. A detailed fine-structure map of the pts gene region is presented.     

Metabolism of Fructooligosaccharides by Lactobacillus paracasei 1195

Fermentation of fructooligosaccharides (FOS) and other oligosaccharides has been suggested to be an important property for the selection of bacterial strains used as probiotics. However, little information is available on FOS transport and metabolism by lactic acid bacteria and other probiotic bacteria. The objectives of this research were to identify and characterize the FOS transport system of Lactobacillus paracasei 1195. Radiolabeled FOS was synthesized enzymatically from [³H]sucrose and purified by column and thin-layer chromatography, yielding three main products: glucose (G) α-1,2 linked to two, three, or four fructose (F) units (GF₂, GF₃, and GF₄, respectively). FOS hydrolysis activity was detected only in cell extracts prepared from FOS- or sucrose-grown cells and was absent in cell supernatants, indicating that transport must precede hydrolysis. FOS transport assays revealed that the uptake of GF₂ and GF₃ was rapid, whereas little GF₄ uptake occurred. Competition experiments showed that glucose, fructose, and sucrose reduced FOS uptake but that other mono-, di-, and trisaccharides were less inhibitory. When cells were treated with sodium fluoride, iodoacetic acid, or other metabolic inhibitors, FOS transport rates were reduced by up to 60%; however, ionophores that abolished the proton motive force only slightly decreased FOS transport. In contrast, uptake was inhibited by ortho-vanadate, an inhibitor of ATP-binding cassette transport systems. De-energized cells had low intracellular ATP concentrations and had a reduced capacity to accumulate FOS. These results suggest that FOS transport in L. paracasei 1195 is mediated by an ATP-dependent transport system having specificity for a narrow range of substrates.     

Continuous production of high-content fructooligosaccharides by a complex cell system

A complex biocatalyst system with a bioreactor equipped with a microfiltration (MF) module was employed to produce high-content fructooligosaccharides (FOS) in a continuous process initiated by a batch process. The system used mycelia of Aspergillus japonicus CCRC 93007 or Aureobasidium pullulans ATCC 9348 with beta-fructofuranosidase activity and Gluconobacter oxydans ATCC 23771 with glucose dehydrogenase activity. Calcium carbonate slurry was used to control pH to 5.5, and gluconic acid in the reaction mixture was precipitated as calcium gluconate. Sucrose solution with an optimum concentration of 30% (w/v) was employed as feed for the complex cell system, and high-content FOS was discharged continuously from a MF module. The complex cell system was run at 30 degrees C with an aeration rate of 5 vvm and produced more than 80% FOS with the remainder being 5-7% glucose and 8-10% sucrose on a dry weight basis, plus a small amount of calcium gluconate. The system worked for a 7-day continuous production process with a dilution rate of 0.04 h(-1), and the volumetric productivity for total FOS was more than 160 g L(-1) h(-1).     

Production of fructooligosaccharides in high yield using a mixed enzyme system of β-fructofuranosidase and glucose oxidase

A mixed enzyme system, with -fructofuranosidase (obtained from Aspergillus japonicus) and commercial glucose oxidase (Gluzyme, Novo Nordisk), produced fructooligosaccharides (FOS) in high yield from sucrose. The reaction was performed in an aerated stirred tank reactor controlled at pH 5.5 by a slurry of CaCO₃. Glucose, an inhibitor of -fructofuranosidase, produced in the reaction was converted by glucose oxidase to gluconic acid, which was then precipitated to calcium gluconate in solution. The system produced more than 90% (w/w) FOS on a dry weight basis, the remainder was glucose, sucrose and a small amount of calcium gluconate. Most of the FOS and sucrose was hydrolyzed to fructose in the mixed enzyme system with glucose oxidase and -fructofuranosidase from Asp. niger.     

Continuous production of high-purity fructooligosaccharides and ethanol by immobilized Aspergillus japonicus and Pichia heimii

High-purity fructooligosaccharides (FOS) were produced from sucrose by an innovative process incorporating immobilized Aspergillus japonicus and Pichia heimii cells. Intracellular FTase of A. japonicus converted sucrose into FOS and glucose, and P. heimii fermented glucose mainly into ethanol. The continuous production of FOS was carried out using a tanks-in-series bioreactor consisting of three stirred tanks. When a solution composed of 1 g L^?1 yeast extract and 300 g L^?1 sucrose was fed continuously to the bioreactor at a dilution rate of 0.1 h^?1, FOS at a purity of up to 98.2 % could be achieved and the value-added byproduct ethanol at 79.6 g L^?1 was also obtained. One gram of sucrose yielded 0.62 g FOS and 0.27 g ethanol. This immobilized dual-cell system was effective for continuous production of high-purity FOS and ethanol for as long as 10 days.     

Metabolism of fructooligosaccharides by Lactobacillus paracasei 1195

Fermentation of fructooligosaccharides (FOS) and other oligosaccharides has been suggested to be an important property for the selection of bacterial strains used as probiotics. However, little information is available on FOS transport and metabolism by lactic acid bacteria and other probiotic bacteria. The objectives of this research were to identify and characterize the FOS transport system of Lactobacillus paracasei 1195. Radiolabeled FOS was synthesized enzymatically from [(3)H]sucrose and purified by column and thin-layer chromatography, yielding three main products: glucose (G) alpha-1,2 linked to two, three, or four fructose (F) units (GF(2), GF(3), and GF(4), respectively). FOS hydrolysis activity was detected only in cell extracts prepared from FOS- or sucrose-grown cells and was absent in cell supernatants, indicating that transport must precede hydrolysis. FOS transport assays revealed that the uptake of GF(2) and GF(3) was rapid, whereas little GF(4) uptake occurred. Competition experiments showed that glucose, fructose, and sucrose reduced FOS uptake but that other mono-, di-, and trisaccharides were less inhibitory. When cells were treated with sodium fluoride, iodoacetic acid, or other metabolic inhibitors, FOS transport rates were reduced by up to 60%; however, ionophores that abolished the proton motive force only slightly decreased FOS transport. In contrast, uptake was inhibited by ortho-vanadate, an inhibitor of ATP-binding cassette transport systems. De-energized cells had low intracellular ATP concentrations and had a reduced capacity to accumulate FOS. These results suggest that FOS transport in L. paracasei 1195 is mediated by an ATP-dependent transport system having specificity for a narrow range of substrates.     

A short-term ingestion of fructo-oligosaccharides increases immunoglobulin A and mucin concentrations in the rat cecum,but the effects are attenuated with the prolonged ingestion

We examined the effects of fructo-oligosaccharides (FOS) on IgA and mucin secretion in the rat cecum after different ingestion periods. Rats were fed a control diet or a diet containing FOS for 1, 2, 4, and 8 wk. FOS ingestion greatly increased IgA and mucin concentrations at 1 and 2 wk, but the effects were disappeared or attenuated at 4 and 8 wk. After 1 wk, FOS induced higher lactobacilli and lactate concentrations and lower cecal pH in the cecum, but the alterations were moderated with the prolonged ingestion accompanying with increasing short-chain fatty acid concentrations. At 1 and 2 wk, FOS increased IgA plasma cells and polymeric immunoglobulin receptor expression in the cecal mucosa and strongly depressed fecal mucinase activities related to the lower cecal pH. These findings may explain the FOS-induced early elevation of IgA and mucin. Clearly, FOS effects on IgA and mucin secretion considerably differ depending on the ingestion period.     

In vitro assessment of the antibacterial effects of the combinations of fosfomycin,colistin, trimethoprim and nitrofurantoin against multi-drug–resistant Escherichia coli

MDR UPEC has become a global health challenge. Our study investigates the pairwise interactions among FOS, COL, NIT and TRI against 29 UPEC strains using the checkerboard method. The synergistic combinations are further evaluated for their bactericidal effects against the most resistant strain (MRS) using the time-kill method. The results showed that 100% of these strains were resistant to TRI and NIT, whereas 75·86% of them were susceptible to FOS and COL. Among all tested strains, only seven strains were highly resistant to all used antibiotics. Remarkably, FOS/COL, COL/NIT and COL/TRI combinations represent the most effective synergistic (fractional inhibitory concentration index <1) combinations against the seven strains at MICs lower than the susceptible breakpoint ranges, followed by FOS/NIT and FOS/TRI, which achieved synergistic interactions against 1/7 and 2/7 of these strains. Importantly, the bactericidal effects (reduction ≥3·0 log₁₀ CFU per ml) were only observed with FOS/COL, COL/NIT and COL/TRI combinations against MRS after 24 h of post-treatment. Our data suggested that FOS/COL, COL/NIT and COL/TRI combinations could be a promising option against MDR UPEC infections. Additionally, FOS/NIT and FOS/TRI probably represent a good option for MDR UPEC with lower MICs.