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Acetobacter aceti NBRC 14818 shows a diauxic growth profile and temporarily accumulates acetate when grown in medium containing ethanol. However, the mechanisms underlying the metabolic switching between the incomplete oxidation of ethanol and overoxidation of acetate, and the control of stress resistance systems in A. aceti cells grown on ethanol are not fully understood. In this study, time-dependent transcriptome changes in cells during growth on ethanol were analyzed by DNA microarray. In A. aceti, ethanol is oxidized to acetate via acetaldehyde by sequential reactions of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). We found that the genes encoding pyrroloquinoline quinone-dependent ADH, membrane-bound ALDH, and two NAD(+)-ADHs were expressed constitutively in cells throughout the culture period. In contrast, the expression levels of genes encoding tricarboxylic acid (TCA) cycle enzymes were low during acetate accumulation until ethanol was consumed, but were significantly upregulated after the accumulated acetate was started to be consumed. This result suggests that changes in the carbon metabolic flow through the TCA cycle are important for the metabolic switching from acetate accumulation to the overoxidation of acetate. In addition, the genes for glyoxylate pathway enzymes were significantly upregulated soon after the cells began oxidizing ethanol, indicating that this pathway is important for the utilization of ethanol as a carbon source., (Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

The strain KCTC 11629BP, isolated from spontaneously fermented pine needle extract (FPE), showed fibrinolysis activity. The isolated strain was analyzed in physiological and biochemical experiments. Based on 16S rDNA sequencing and phylogenic tree analysis, the strain was identified to be a part of the genus Acetobacter, with Acetobacter senegalensis and Acetobacter tropicalis as the closest phylogenetic neighbors. Based on genotypic and phenotypic results, it was proposed that bacterial strain KCTC 11629BP represents a species of the genus Acetobacter. The strain was thusly named Acetobacter sp. FP1. In conclusion, Acetobacter sp. FP1 isolated from FPE possesses fibrinolytic activity.

Acetobacter pasteurianus is a Gram-negative strictly aerobic bacterium that is widely used for the industrial production of vinegar. Three Acetobacter pasteurianus strains, SKU1108, NBRC 3283 and IFO 3191, have the same 16S rRNA sequence (100 % sequence identity) but show differences in thermotolerance. To clarify the relationships between phylogeny and thermotolerance of these strains, genome-wide analysis of these three strains was performed. Concatenated phylogenetic analysis of a dataset of 1864 orthologues has shown that the more thermotolerant strains, SKU1108 and NBRC 3283, are more closely related to each other than to the more thermosensitive strain, IFO 3191. In addition, we defined a dataset of 2010 unique orthologues among these three strains, and compared the frequency of amino acid mutations among them. Genes involved in translation, transcription and signal transduction are highly conserved among each unique orthologous dataset. The results also showed that there are several genes with increased mutation rates in IFO 3191 compared with the thermotolerant strains, SKU1108 and NBRC 3283. Analysis of the mutational directions of these genes suggested that some of them might be correlated with the thermosensitivity of IFO 3191. Concatenated phylogenetic analysis of these closely related strains revealed that there is a phylogenetic relationship associated with this phenotype among the thermotolerant and thermosensitive strains.

We have reported that lactobionic acid is produced from lactose by Acetobacter orientalis in traditional Caucasian fermented milk. To maximize the application of lactobionic acid, we investigated favorable conditions for the preparation of resting A. orientalis cells and lactose oxidation. The resting cells, prepared under the most favorable conditions, effectively oxidized 2-10% lactose at 97.2 to 99.7 mol % yield.

Background: Animals are chronically infected by benign and beneficial microorganisms that generally promote animal health through their effects on the nutrition, immune function and other physiological systems of the host. Insight into the host-microbial interactions can be obtained by comparing the traits of animals experimentally deprived of their microbiota and untreated animals. Drosophila melanogaster is an experimentally tractable system to study host-microbial interactions., Methodology/principal Findings: The nutritional significance of the microbiota was investigated in D. melanogaster bearing unmanipulated microbiota, demonstrated by 454 sequencing of 16S rRNA amplicons to be dominated by the α-proteobacterium Acetobacter, and experimentally deprived of the microbiota by egg dechorionation (conventional and axenic flies, respectively). In axenic flies, larval development rate was depressed with no effect on adult size relative to conventional flies, indicating that the microbiota promotes larval growth rates. Female fecundity did not differ significantly between conventional and axenic flies, but axenic flies had significantly reduced metabolic rate and altered carbohydrate allocation, including elevated glucose levels., Conclusions/significance: We have shown that elimination of the resident microbiota extends larval development and perturbs energy homeostasis and carbohydrate allocation patterns of of D. melanogaster. Our results indicate that the resident microbiota promotes host nutrition and interacts with the regulation of host metabolism.

Eleven strains of acetic acid bacteria were isolated from stems of sugarcane, fruits, and a flower in Japan. The isolates were separated into three groups, Groups I, II, and III, in the genus Acetobacter according to phylogenetic analysis based on 16S rRNA sequences. The isolates had sequence similarities of 99.8-100% within the Group, 99.3-99.6% to those of the type strains of each related Acetobacter species, and less than 98.4% to those of the type strains of other Acetobacter species. Genomic DNA G+C contents of Groups I, II, and III were 59.2-59.4, 60.5-60.7, and 58.7-58.9 mol%, respectively. The isolates in the Group showed high values of DNA-DNA relatedness to each other, but low values less than 46% to the type strains of related Acetobacter species. A good correlation was found between the three Groups and groups based on DNA G+C contents and DNA-DNA relatedness. All the strains had Q-9 as the main component, and Q-8 and Q-10 as minor components. The isolates in the three Groups did not completely match with any Acetobacter species on catalase reaction, the production of ketogluconic acids from D-glucose, growth on ammoniac nitrogen with ethanol (Hoyer-Frateur medium and Frateur modified Hoyer medium), growth on 30% (w/v) D-glucose, growth in 10% (v/v) ethanol, or DNA G+C contents. On the basis of phylogenetic relationships in the genus Acetobacter and chemosystematic and phenotypic characteristics, the three Groups were regarded as novel species in the genus Acetobacter. Acetobacter okinawensis sp. nov. is proposed for Group I, Acetobacter papayae sp. nov. for Group II, and Acetobacter persicus sp. nov. for Group III.

Background: Chiral alcohols are widely used in the synthesis of chiral pharmaceuticals, flavors and functional materials and appropriate whole-cell biocatalysts offer a highly enantioselective, minimally polluting route to these valuable compounds. The recently isolated strain Acetobacter sp. CCTCC M209061 showed exclusive anti-Prelog stereoselectivity for the reduction of prochiral ketones, but the low biomass has limited its commercialization and industrial applications. To tackle this problem, the effects of medium components and culture conditions on the strain's growth and reduction activity were explored., Results: By using a one-at-a-time method and a central composite rotatable design (CCRD), the optimal medium and culture conditions were found to be as follows: glucose 8.26 g/L, fructose 2.50 g/L, soy peptone 83.92 g/L, MnSO4·H2O 0.088 g/L, pH 5.70, 30°C and 10% (v/v) inoculum. Under the above-mentioned conditions, the biomass after 30 h cultivation reached 1.10 ± 0.03 g/L, which was 9.5-fold higher than that obtained with basic medium. Also, the reduction activity towards 4'-chloroacetophenone was markedly enhanced to 39.49 ± 0.96 μmol/min/g from 29.34 ± 0.65 μmol/min/g, with the product e.e. being above 99%. Comparable improvements were also seen with the enantioselective bioreduction of 4-(trimethylsilyl)-3-butyn-2-one to the key pharmaceutical precursor (R) - 4-(trimethylsilyl)-3-butyn-2-ol., Conclusions: The biomass and reduction activity of Acetobacter sp. CCTCC M209061 can be greatly enhanced through the optimization strategy. This facilitates use of the strain in the anti-Prelog stereoselective reduction of prochiral ketones to enantiopure chiral alcohols as building blocks for many industries.

Background: Fermented rice flour (khao-khab, a non-glutinous rice) and related products are Thai traditional products. The types of acetic acid bacteria (AAB) microflora in khao-khab have not been reported. In this study, Acetobacter strains were isolated and identified based on the phenotypic and chemotaxonomic characteristics and molecular aspects., Results: Twenty-five acetic acid bacteria isolated from fermented rice products and a starter for sweetened rice in Thailand by an enrichment culture approach, were assigned to the genus Acetobacter by phenotypic and chemotaxonomic characterisations. On the basis of the 16S rRNA gene sequence and 16S-23S rRNA gene ITS restriction analyses, 25 isolates were divided into six groups and identified at the specific level: (1) Group 1 included five isolates, which were identified as A. indonesiensis; (2) Group 2 included two isolates, which were identified as A. lovaniensis; (3) Group 3 included one isolate, which was identified as A. orientalis; (4) Group 4 included eleven isolates, which were identified as A. pasteurianus; (5) Group 5 included three isolates, which were identified as A. syzygii and (6) Group 6 included three isolates, which were unidentified and considered to constitute a new species., Conclusion: Results revealed that various Acetobacter species were distributed in Thai fermented rice flour and related products. A novel Acetobacter species was isolated from the product., (Copyright © 2011 Society of Chemical Industry.)

The cytosolic NAD⁺-dependent alcohol dehydrogenases (NAD⁺-ADHs) are induced in the quinoprotein ADH-(PQQ-ADH) defective Acetobacter pasteurianus SKU1108 mutant during growth in an ethanol medium. The adhI and adhII genes, which encode NAD⁺-ADH I and ADH II, respectively, of this strain have been cloned and characterized. Sequence analyses have revealed that the adhI gene consists of 1029 bp coding for 342 amino acids, which share 99.71% identity with the same protein from A. pasteurianus IFO 3283. Conversely, the adhII gene is composed of 762 bp encoding for a polypeptide of 253 amino acids, which exhibit 99.60% identity with the A. pasteurianus IFO 3283 protein. ADH I is a member of the group I Zn-dependent long-chain ADHs, while the ADH II belongs to the group II short-chain dehydrogenase/reductase NAD⁺-ADHs. The NAD⁺-adh gene disruptants exhibited a growth reduction when grown in an ethanol medium. In Escherichia coli, ethanol induced adhI and adhII promoter activities by approximately 1.5 and 2.0 times, respectively, and the promoter activity of the adhII gene exceeded that of the adhI gene by approximately 3.5 times. The possible promoter regions of the adhI and adhII genes are located at approximately 81-105 bp and 74-92 bp, respectively, from their respective ATG start codons. Their repressor regions might be located in proximity to these promoters and may repress gene expression in the wild-type, where the membrane-bound ADH effectively functions., (Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

The purification and characterization of an extracellular levansucrase enzyme produced by novel nitrogen-fixer Acetobacter nitrogenifigens strain RG1(T) is described. Culture conditions were optimized for maximum levansucrase production. Levansucrase purified to homogeneity by tenfold purification has a molecular weight of 65 kDa, contained four cysteine residues, polymerized raffinose and was stable for 21 days at pH 6.0 when stored at 4 °C or -20 °C but was vulnerable to DTT and β-mercaptoethanol. Interestingly, this enzyme showed enhanced hydrolytic and polymerization activity in the presence of mercuric ion which, to our knowledge, is the first report for any levansucrase enzyme characterized so far. Evidences obtained from Native PAGE, tryptophan fluorescence study and activity measurements at different temperatures and in the presence of thiol modifying agents, show that mercuric ion stabilizes the enzyme. Levan, synthesized by the enzyme, has a molecular weight of 7,080 kDa and was shown to be a homopolymer of fructose.

The RpoH in Acetobacter pasteurianus NBRC3283 was characterized. It was revealed that the rpoH controls the expression of groEL, dnaKJ, grpE, and clpB to different extents. In addition, the rpoH disruption mutant became apt to be affected by heat, ethanol, and acetic acid, indicating its importance in acetic acid fermentation., (Copyright © 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

The draft genome sequence of Acetobacter aceti NBRC 14818 was determined by whole-genome shotgun sequencing and the transcriptome profile in cells exponentially grown on ethanol, acetate or glucose was analysed by using a DNA microarray. The genes for all enzymes that constitute the complete tricarboxylic acid (TCA) cycle and glyoxylate pathway were identified in the genome. The TCA cycle genes showed higher expression levels in A. aceti cells grown on acetate or glucose and the glyoxylate pathway genes were significantly induced by ethanol or acetate. Many SOS-response genes were upregulated in cells grown on ethanol, indicating that ethanol provoked damage of DNA and proteins. The superoxide dismutase and catalase genes showed high expression levels in culture on glucose, indicating that oxidation of glucose induced oxidative stress. A. aceti NBRC 14818 was found to have a highly branched respiratory chain. The genes for two type I and one type II NADH dehydrogenase were identified. The genes for one of the type I enzymes were highly expressed when cells were grown on acetate or glucose, but were significantly downregulated in culture on ethanol, probably because ubiquinones were directly reduced by pyrroloquinoline quinone-dependent alcohol dehydrogenase. Four sets of the genes for quinol oxidases, one bo(3)-type (BO3), one bd-type and two cyanide-insensitive-types (CIOs), were identified in the genome. The genes for BO3, which might have proton-pumping activity, were highly expressed under the conditions tested, but were downregulated in the glucose culture. In contrast, the genes for one of the CIOs were significantly upregulated in cells grown on glucose. The two CIOs, which are expected to have lower energy-coupling efficiency, seemed to have a higher contribution in glucose-grown cells. These results indicate that energy conservation efficiency is fine-tuned by changing the respiratory components according to the growth conditions in A. aceti cells.

Acetobacter tropicalis NBRC16470 can produce highly enantiomerically pure D-glyceric acid (D-GA; >99 % enantiomeric excess) from glycerol. To investigate whether membrane-bound alcohol dehydrogenase (mADH) is involved in GA production in A. tropicalis, we amplified part of the gene encoding mADH subunit I (adhA) using polymerase chain reaction and constructed an adhA-disrupted mutant of A. tropicalis (ΔadhA). Because ΔadhA did not produce GA, we confirmed that mADH is essential for the conversion of glycerol to GA. We also cloned and sequenced the entire region corresponding to adhA and adhB, which encodes mADH subunit II. The sequences showed high identities (84-86 %) with the equivalent mADH subunits from other Acetobacter spp.

The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes.

The aim of this research was the application of a two-stage electrodialysis (ED) method for glyceric acid (GA) recovery from fermentation broth. First, by desalting ED, glycerate solutions (counterpart is Na+) were concentrated using ion-exchange membranes, and the glycerate recovery and energy consumption became more efficient with increasing the initial glycerate concentration (30 to 130 g/l). Second, by water-splitting ED, the concentrated glycerate was electroconverted to GA using bipolar membranes. Using a culture broth of Acetobacter tropicalis containing 68.6 g/l of D-glycerate, a final D-GA concentration of 116 g/l was obtained following the two-stage ED process. The total energy consumption for the D-glycerate concentration and its electroconversion to D-GA was approximately 0.92 kWh per 1 kg of D-GA., (Copyright © 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Objective: To acclimate, screen the dominant bacteria for degrading pentachlorophenol and its growth characteristics and degradation conditions study., Methods: Active sludge aeration and method of density gradient were used to acclimate the sludge. Using pentachlorophenol as a sole carbon source, it was increased step by step in continuous eight weeks. The biodegradation test on pentachlorophenol was conducted after isolation, purification of the dominant bacteria. The suitable temperature, the growth characteristics under different osmotic pressure and the proper degradation conditions of the dominant bacteria were investigated. According to the morphological characteristic, physiological and biochemical, the strain was preliminarily identified., Results: Three strains of dominant bacteria were screened. The degradation rates of one strain among them on pentachlorophenol could reach to 98.64% in 48 h. The degradation effect would be better when the temperature was 30 degrees C, pH was 6, and the concentration of pentachlorophenol was 0.2-0.4 g/L. The strain could grow best under 30 degrees C. It was halotolerant bacteria and identified as Acetobacter., Conclusion: The dominant bacteria could be got through density gradient acclimatization in the active sludge aeration basin and its degradation effect on pentachlorophenol was obvious.

We prepared 2-hydroxypalmitoyl-sphinganine (dihydroceramide) labeled with a stable isotope by culturing acetic acid bacteria with (13)C-labeled acetic acid. The GC/MS spectrum of the trimethylsilyl derivative of (13)C-labeled dihydroceramide gave molecular ions with an increased mass of 12-17 Da over that of nonlabeled dihydroceramide. The fragment ions derived from both sphinganine base and 2-hydroxypalmitate were confirmed to be labeled with the stable isotope in the spectrum. Therefore, (13)C-labeled dihydroceramide can be an extremely useful tool for analyzing sphingolipid metabolism. The purified [(13)C]dihydroceramide was administered orally to mice for 12 days, and the total sphingoid base fractions in various tissues were analyzed by GC/MS. The spectrum patterns specific to (13)C-labeled sphingoids were detected in the tissues tested. Sphinganine pools in skin epidermis, liver, skeletal muscle, and synapse membrane in brain were replaced by [(13)C]sphinganine at about 4.5, 4.0, 1.0, and 0.3%, respectively. Moreover, about 1.0% of the sphingosine pool in the liver was replaced by [(13)C]sphingosine, implying that exogenous dihydroceramide can be converted to sphingosine. These results clearly indicate that ingested dihydroceramide can be incorporated into various tissues, including brain, and metabolized to other sphingolipids.

The clpB gene in Acetobacter pasteurianus was cloned and characterized. Although the clpB gene was transcribed in response to a temperature shift and exposure to ethanol, the clpB disruption mutant was only affected by high temperature, suggesting that the ClpB protein is closely associated with heat resistance in A. pasteurianus., (2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Acetic acid bacteria, fermentative microorganisms of traditional foods, have unique alkali-stable lipids (ASL), such as dihydroceramide which is a precursor of sphingolipids. Sphingolipids are important components of the brain tissue. We examined the effect of oral administration of ASL in a rat model of dementia (7-week-old, male) with a basal forebrain lesion. In a water maze test, the dementia model rats demonstrated poor spatial orientation. The administration of ASL (165 or 1650 mg/kg of body weight per day, for 14 days) produced a significant improvement in learning ability in the dementia model rats. In vitro experiments showed ASL had the ability to promote neurite outgrowth in pheochromocytoma (PC12) cells. Among the ASL components, dihydroceramide has the most potent effect on the differentiation of PC12 cells. It is highly possible that oral administration of dihydroceramide-containing ASL reverses the decline in cognitive function in dementia.

Vinegar production is based on the acetification process by indigenous acetic acid bacteria (AAB). Among vinegar technologies, solid-state fermentation (SSF) processes are widespread in Asian countries to produce vinegar at small-scale. In this study, 21 AAB strains isolated from Chinese cereal vinegars produced by SSF collected in different regions of China were characterized by enterobacterial repetitive intergenic consensus (ERIC)-PCR fingerprinting. Isolates exhibited high degree of phenotypic variability as well as suitable traits for their uses as selected strains in SSF vinegar production (growth modality by superficial biofilm, no production of cellulose, ability to growth on ethanol media). 16S rRNA gene sequencing analysis of representative strains showed that strains of Acetobacter pasteurianus have a close association to cereal vinegars, whereas Gluconacetobacter europaeus population is not favoured. Selection of single or multiple strains culture within A. pasteurianus species was predicted in view of their application in SSF technology. This seems to be the first report showing phenotypic and genetic variability of AAB strains involved in SSF processes. Results can be exploited for the implementation of large-scale SSF processes by selected strains for vinegar production and other innovative biotechnological applications.

The population dynamics of acetic acid bacteria in traditional vinegar production was determined in two independent vinegar plants at both the species and strain level. The effect of barrels made of four different woods upon the population dynamics was also determined. Acetic acid bacteria were isolated on solid media and the species were identified by RFLP-PCR of 16S rRNA genes and confirmed by 16S rRNA gene sequencing, while strains were typed by ERIC-PCR and (GTG)(5)-rep-PCR. The most widely isolated species was Acetobacter pasteurianus, which accounted for 100% of all the isolates during most of the acetification. Gluconacetobacter europaeus only appeared at any notable level at the end of the process in oak barrels from one vinegar plant. The various A. pasteurianus strains showed a clear succession as the concentration of acetic acid increased. In both vinegar plants the relative dominance of different strains was modified as the concentrations of acetic acid increased, and strain diversity tended to reduce at the end of the process., (Copyright 2010 Elsevier B.V. All rights reserved.)

We administered Acetobacter malorum NCI1683 (S24), containing a high concentration of dihydroceramide (7.2 mg/g of dry cell weight), consecutively to aged rats (male Crlj:Wistar rats, 22 months old). The ingestion of Acetobacter malorum for 89 d significantly extended the memory retention in passive avoidance tests, increased the release of acetylcholine with depolarization of brain synaptosomes and decreased the causative agents of neurodegenerative diseases in the cerebral cortices.

The grpE gene in Acetobacter pasteurianus NBRC 3283 was cloned and characterized, to elucidate the mechanism underlying the resistance of acetic acid bacteria to the stressors existing during acetic acid fermentation. This gene was found to be located in tandem with two related genes, appearing on the genome in the order grpE-dnaK-dnaJ. A sigma(32)-type promoter sequence was found in the upstream region of grpE. The relative transcription levels of grpE, dnaK, and dnaJ mRNA were in the ratio of approximately 1:2:0.1, and the genes were transcribed as grpE-dnaK, dnaK, and dnaJ. The transcription level of grpE was elevated by heat shock and treatment with ethanol. Co-overexpression of GrpE with DnaK/J in cells resulted in improved growth compared to the single overexpression of DnaK/J in high temperature or ethanol-containing conditions, suggesting that GrpE acts cooperatively with DnaK/J for expressing resistance to those stressors considered to exist during acetic acid fermentation. Our findings indicate that GrpE is closely associated with adaptation to stressors in A. pasteurianus and may play an important role in acetic acid fermentation., (2009. Published by Elsevier B.V.)

Acetic acid bacteria have unique and highly pure membrane lipid components, such as 2-hydroxypalmitoyl-sphinganine (dihydroceramide) and can grow and produce acetic acid at around pH 3.0, suggesting that ceramide in cell membranes may be involved in the tolerance to acidic pH. Acetobacter malorum S24 was selected for the production of ceramide and grown in YPG medium containing 0.8% ethanol. Ceramide biosynthesis was induced at pH 4 and below, suggesting that ceramide biosynthesis is induced by low pH stress. Elevation of ceramide was also induced by high temperature stress (40-70 degrees C). After the strain was cultured in an optimal growth medium, the cells were collected and treated at pH 3 and 40 degrees C for 4 days, resulting in a 30-fold elevation of both the yield and content of ceramide., (2009. Published by Elsevier B.V.)

Acetobacter pasteurianus strains IFO3283, SKU1108, and MSU10 were grown under acetic acid fermentation conditions, and their growth behavior was examined together with their capacity for acetic acid resistance and pellicle formation. In the fermentation process, the cells became aggregated and covered by amorphous materials in the late-log and stationary phases, but dispersed again in the second growth phase (due to overoxidation). The morphological change in the cells was accompanied by changes in sugar contents, which might be related to pellicle polysaccharide formation. To determine the relationship between pellicle formation and acetic acid resistance, a pellicle-forming R strain and a non-forming S strain were isolated, and their fermentation ability and acetic acid diffusion activity were compared. The results suggest that pellicle formation is directly related to acetic acid resistance ability, and thus is important to acetic acid fermentation in these A. pasteurianus strains.

The biocatalytic reduction of 4-(trimethylsilyl)-3-butyn-2-one to enantiopure (R)-4-(trimethylsilyl)-3-butyn-2-ol was successfully conducted with high enantioselectivity using immobilized whole cells of a novel strain Acetobacter sp. CCTCC M209061, newly isolated from kefir. Compared with other microorganisms that were investigated, Acetobacter sp. CCTCC M209061 was shown to be more effective for the bioreduction reaction, and afforded much higher yield and product enantiomeric excess (e.e.). The optimal buffer pH, co-substrate concentration, reaction temperature, substrate concentration and shaking rate were 5.0, 130.6 mM, 30 degrees C, 6.0 mM and 180 r/min, respectively. Under the optimized conditions, the maximum yield and the product e.e. were 71% and >99%, respectively, which are much higher than those reported previously. Additionally, the established biocatalytic system proved to be efficient for the bioreduction of acetyltrimethylsilane to (R)-1-trimethylsilylethanol with excellent yield and product e.e. The immobilized cells manifested a good operational stability under the above reaction conditions since they retained 70% of their catalytic activity after ten cycles of use.

Glyceric acid (GA), an unfamiliar biotechnological product, is currently produced as a small by-product of dihydroxyacetone production from glycerol by Gluconobacter oxydans. We developed a method for the efficient biotechnological production of GA as a target compound for new surplus glycerol applications in the biodiesel and oleochemical industries. We investigated the ability of 162 acetic acid bacterial strains to produce GA from glycerol and found that the patterns of productivity and enantiomeric GA compositions obtained from several strains differed significantly. The growth parameters of two different strain types, Gluconobacter frateurii NBRC103465 and Acetobacter tropicalis NBRC16470, were optimized using a jar fermentor. G. frateurii accumulated 136.5 g/liter of GA with a 72% d-GA enantiomeric excess (ee) in the culture broth, whereas A. tropicalis produced 101.8 g/liter of d-GA with a 99% ee. The 136.5 g/liter of glycerate in the culture broth was concentrated to 236.5 g/liter by desalting electrodialysis during the 140-min operating time, and then, from 50 ml of the concentrated solution, 9.35 g of GA calcium salt was obtained by crystallization. Gene disruption analysis using G. oxydans IFO12528 revealed that the membrane-bound alcohol dehydrogenase (mADH)-encoding gene (adhA) is required for GA production, and purified mADH from G. oxydans IFO12528 catalyzed the oxidation of glycerol. These results strongly suggest that mADH is involved in GA production by acetic acid bacteria. We propose that GA is potentially mass producible from glycerol feedstock by a biotechnological process.

Acetobacter aceti and Gluconobacter roseus, which are known to be responsible for the spoilage of wine, are used for current generation in batch-type microbial biofuel cells and it has been shown for the first time that these two microorganisms do not require mediators for the transfer of electrons to the anode. Three biofuel cells were constructed with two cells containing the pure cultures of each of the microorganisms as the biocatalyst (A-MFC, G-MFC) and the third cell was constructed with the mixed culture of these two microorganisms as the biocatalyst (AG-MFC). The performance of the biofuel cells was evaluated in terms of open circuit voltage (OCV), fuel consumption rate, internal resistance, power output, and coulombic efficiency. The mixed culture cell (AG-MFC) exhibits a better overall performance compared to the other cells.

Acetobacter species have been used for brewing traditional vinegar and are known to have genetic instability. To clarify the mutability, Acetobacter pasteurianus NBRC 3283, which forms a multi-phenotype cell complex, was subjected to genome DNA sequencing. The genome analysis revealed that there are more than 280 transposons and five genes with hyper-mutable tandem repeats as common features in the genome consisting of a 2.9-Mb chromosome and six plasmids. There were three single nucleotide mutations and five transposon insertions in 32 isolates from the cell complex. The A. pasteurianus hyper-mutability was applied for breeding a temperature-resistant strain grown at an unviable high-temperature (42 degrees C). The genomic DNA sequence of a heritable mutant showing temperature resistance was analyzed by mutation mapping, illustrating that a 92-kb deletion and three single nucleotide mutations occurred in the genome during the adaptation. Alpha-proteobacteria including A. pasteurianus consists of many intracellular symbionts and parasites, and their genomes show increased evolution rates and intensive genome reduction. However, A. pasteurianus is assumed to be a free-living bacterium, it may have the potentiality to evolve to fit in natural niches of seasonal fruits and flowers with other organisms, such as yeasts and lactic acid bacteria.

This study aimed to reduce post-harvest losses of pineapple local variety egbenana by the transformation of juice into vinegar through biotechnological process. Vinegar was produced through two successive fermentations: alcoholic and acetic fermentations. The alcohol fermentation was carried out at 30 degrees C using yeast. Biomass, pH and Brix were evaluated daily during the fermentation. Acetic fermentation was carried out at 30 degrees C using an acetic bacteria strain isolated from pineapple wine previously exposed to ambient temperature (28 degrees C) for 5 days. Biomass, pH and acid levels were monitored each 2 days. The performance of acetic bacteria isolated was also assessed by studying their glucose and ethanol tolerance. The study allowed the isolation of yeast coded Saccharomyces cerevisiae (LAS01) and an acetic bacteria coded Acetobacter sp. (ASV03) both occurring in the pineapple juice. The monitoring of successive fermentations indicated that the pineapple juice with sugar concentration of 20 Brix, seeded with 10(6) cells of Saccharomyces cerevisiae (LAS01) for alcoholic fermentation for 4 days and afterwards seeded with 10(6) cells of Acetobacter sp. resulted in 4.5 acetic degree vinegar at Brix 5.3% and pH 2.8 for 23 to 25 days. The study of glucose tolerance of the strain of Acetobacter sp. showed that the growth of acetic bacteria was important in a juice with high concentration of sugar. However, the concentration of ethanol did not effect on the acetic bacteria growth. These results enabled on one hand to improve the manufacturing technology of vinegar from fruits and on the other hand to produce a starter of yeast and acetic bacteria strains for this production.

The application of a selected Acetobacter pasteurianus strain for traditional balsamic vinegar production was assessed. Genomic DNA was extracted from biofilms after enrichment cultures on GYC medium (10% glucose, 1.0% yeast extract, 2.0% calcium carbonate) and used for PCR/denaturing gradient gel electrophoresis, 16S rRNA gene sequencing, and enterobacterial repetitive intergenic consensus/PCR sequencing. Results suggested that double-culture fermentation is suitable for traditional balsamic vinegar acetification.

Glyceric acid is produced by the conversion of glycerol via bioprocesses. The glycerate recovery from model solutions and from real culture broth was demonstrated by a desalting electrodialysis (ED) method. The addition of several impurities in glycerate model solutions, such as polypepton or yeast extract, did not have significant adverse effects on the whole ED process, and more than 93% of the glycerol added in the model solutions (50-150 g/l) was excluded. Using culture broth of Acetobacter tropicalis containing 14.6 g/l D-glycerate, the D-glycerate recovery and the energy consumption were 99.4% and 0.24 kWh/kg, respectively.

Kombucha tea (KT) is sugared black tea fermented with a symbiotic culture of acetic acid bacteria and yeasts, which is said to be tea fungus. KT is claimed to have various beneficial effects on human health, but there is very little scientific evidence available in the literature. In the present study, KT along with black tea (BT) and black tea manufactured with tea fungus enzymes (enzyme-processed tea, ET) was evaluated for hepatoprotective and curative properties against CCl4-induced toxicity, using male albino rats as an experimental model by analyzing aspartate transaminase, alanine transaminase, and alkaline phosphatase in plasma and malondialdehyde content in plasma and liver tissues. Histopathological analysis of liver tissue was also included. Results showed that BT, ET, and KT have the potential to revert the CCl4-induced hepatotoxicity. Among the three types of teas tried, KT was found to be more efficient than BT and ET. Antioxidant molecules produced during the fermentation period could be the reason for the efficient hepatoprotective and curative properties of KT against CCI4-induced hepatotoxicity.

Bacterial strains capable of converting glycerol to glyceric acid (GA) were screened among the genera Acetobacter and Gluconacetobacter. Most of the tested Acetobacter and Gluconacetobacter strains could produce 1.8 to 9.3 g/l GA from 10% (v/v) glycerol when intact cells were used as the enzyme source. Acetobacter tropicalis NBRC16470 was the best GA producer and was therefore further investigated. Based on the results of high-performance liquid chromatography analysis and specific rotation, the enantiomeric composition of the produced GA was D-glyceric acid (D-GA). The productivity of D-GA was enhanced with the addition of both 15% (v/v) glycerol and 20 g/l yeast extract. Under these optimized conditions, A. tropicalis NBRC16470 produced 22.7 g/l D-GA from 200 g/l glycerol during 4 days of incubation in a jar fermentor.

Carboxymethyl cellulose from nata de coco, referred to as carboxymethyl-nata (CMN), was prepared by two cycles of mercerization and etherification. Coatings containing 1% and 2% CMN were applied on bell peppers to evaluate the effect of the polysaccharide coating on the post-harvest life of the fruits. The fruits were stored at 25 degrees C. During storage, the color change in CMN-coated fruits was slower than in the control and blank fruits (coated with additives only). CMN-coated fruits maintained firmness and had lower weight loss, total soluble solids content and titratable acidity than the control and blank. Antioxidant activity and total phenolic content increased from day 0 to day 15. CMN-coated fruits had lower total phenolic content than the control and blank at day 15. Values at day 15 did not indicate the retardation of antioxidant activity in the 1% CMN-coated fruits. Results indicated that CMN coatings reduced the rate of ripening.

Lactobionic acid was first found in a Caucasian fermented milk product popularly known as "Caspian Sea yogurt" in Japan. The presence of lactobionic acid in the fermented milk was indicated by the results of both high-performance anion-exchange chromatographic analysis with pulsed amperometric detection and mass spectrometric analysis. Thereafter, the acid was purified from the yogurt and analyzed by nuclear magnetic resonance. A substantial amount of lactobionic acid was found to be accumulated in the upper layer of the yogurt, especially within 10 mm from the surface. A total of 45 mg of lactobionic acid per 100 g of the upper yogurt layer was collected after 4 d of fermentation. The annual intake of lactobionic acid in individuals consuming 100 g of the yogurt every day would be 0.5 to 1.0 g. A lactose-oxidizing bacterium was isolated from the fermented milk and was identified as Acetobacter orientalis. Washed A. orientalis cells oxidized monosaccharides such as d-glucose at considerable rates, although their activities for substrates such as lactose, maltose, and cellobiose were much lower. When A. orientalis cells were cultivated in cow's milk, they exhibited lactose-oxidizing activity, suggesting that this bacterium was the main organism involved in the production of lactobionic acid in the yogurt.

The bacterium Acetobacter pasteurianus can ferment acetic acid, a process that proceeds at the risk of oxidative stress. To understand the stress response, we investigated catalase and OxyR in A. pasteurianus NBRC3283. This strain expresses only a KatE homolog as catalase, which is monofunctional and growth dependent. Disruption of the oxyR gene increased KatE activity, but both the katE and oxyR mutant strains showed greater sensitivity to hydrogen peroxide as compared to the parental strain. These mutant strains showed growth similar to the parental strain in the ethanol oxidizing phase, but their growth was delayed when cultured in the presence of acetic acid and of glycerol and during the acetic acid peroxidation phase. The results suggest that A. pasteurianus cells show different oxidative stress responses between the metabolism via the membrane oxidizing pathway and that via the general aerobic pathway during acetic acid fermentation.

Acetic acid bacteria (AAB) are considered fastidious microorganisms because they are difficult to isolate and cultivate. Different molecular approaches were taken to detect AAB diversity, independently of their capacity to grow in culture media. Those methods were tested in samples that originated during traditional vinegar production. Bacterial diversity was assessed by analysis of 16S rRNA gene, obtained by PCR amplifications of DNA extracted directly from the acetification container. Bacterial composition was analyzed by RFLP-PCR of 16S rRNA gene, Temporal Temperature Gradient Gel Electrophoresis (TTGE) separation of amplicons containing region V3-V5 of 16S rRNA gene and cloning of those amplicons. TTGE bands and clones were grouped based on their electrophoretic pattern similarity and sequenced to be compared with reference strains. The main microorganism identified in vinegar was Acetobacter pasteurianus, which at the end of the acetification process was considered to be the only microorganism present. The diversity was the highest at 2% acetic acid, where indefinite species of Gluconacetobacter xylinus/europaeus/intermedius were also present.

Taxonomic studies of acetic acid bacteria were historically surveyed. The genus Acetobacter was first introduced in 1898 with a single species, Acetobacter aceti. The genus Gluconobacter was proposed in 1935 for strains with intense oxidation of glucose to gluconic acid rather than oxidation of ethanol to acetic acid and no oxidation of acetate. The genus "Acetomonas" was described in 1954 for strains with polar flagellation and no oxidation of acetate. The proposals of the two generic names were due to confusion, and "Acetomonas" was a junior subjective synonym of Gluconobacter. The genus Acetobacter was in 1984 divided into two subgenera, Acetobacter and Gluconoacetobacter. The latter was elevated to the genus Gluconacetobacter in 1998. In the acetic acid bacteria, ten genera are presently recognized and accommodated to the family Acetobacteraceae, the Alphaproteobacteria: Acetobacteer, Gluconobacter, Acidomonas, Gluconacetobacter, Asaia, Kozakia, Swaminathania, Saccharibacter, Neoasaia and Granulibacter. In contrast, the genus Frateuria, strains of which were once named 'pseudacetic acid bacteria', was classified into the Gammaproteobacteria. The genus Gluconacetobacter was phylogenetically divided into two groups: the Gluconacetobacter liquefaciens group and the Gluconacetobacter xylinus group. The two groups were discussed taxonomically.

Amplification of repetitive bacterial DNA elements through the polymerase chain reaction (rep-PCR fingerprinting) using the (GTG)(5) primer, referred to as (GTG)(5)-PCR fingerprinting, was found a promising genotypic tool for rapid and reliable speciation of acetic acid bacteria (AAB). The method was evaluated with 64 AAB reference strains, including 31 type strains, and 132 isolates from Ghanaian, fermented cocoa beans, and was validated with DNA:DNA hybridization data. Most reference strains, except for example all Acetobacter indonesiensis strains and Gluconacetobacter liquefaciens LMG 1509, grouped according to their species designation, indicating the usefulness of this technique for identification to the species level. Moreover, exclusive patterns were obtained for most strains, suggesting that the technique can also be used for characterization below species level or typing of AAB strains. The (GTG)(5)-PCR fingerprinting allowed us to differentiate four major clusters among the fermented cocoa bean isolates, namely A. pasteurianus (cluster I, 100 isolates), A. syzygii- or A. lovaniensis-like (cluster II, 23 isolates), and A. tropicalis-like (clusters III and IV containing 4 and 5 isolates, respectively). A. syzygii-like and A. tropicalis-like strains from cocoa bean fermentations were reported for the first time. Validation of the method and indications for reclassifications of AAB species and existence of new Acetobacter species were obtained through 16S rRNA sequencing analyses and DNA:DNA hybridizations. Reclassifications refer to A. aceti LMG 1531, Ga. xylinus LMG 1518, and Ga. xylinus subsp. sucrofermentans LMG 18788(T).

Acetic acid bacteria (AAB) are ubiquitous organisms that are well adapted to sugar and ethanol rich environments. This family of Gram-positive bacteria are well known for their ability to produce acetic acid, the main constituent in vinegar. The oxidation of ethanol through acetaldehyde to acetic acid is well understood and characterised. AAB form part of the complex natural microbial flora of grapes and wine, however their presence is less desirable than the lactic acid bacteria and yeast. Even though AAB were described by Pasteur in the 1850s, wine associated AAB are still difficult to cultivate on artificial laboratory media and until more recently, their taxonomy has not been well characterised. Wine is at most risk of spoilage during production and the presence of these strictly aerobic bacteria in grape must and during wine maturation can be controlled by eliminating, or at least limiting oxygen, an essential growth factor. However, a new risk, spoilage of wine by AAB after packaging, has only recently been reported. As wine is not always sterile filtered prior to bottling, especially red wine, it often has a small resident bacterial population (<10(3) cfu/mL), which under conducive conditions might proliferate. Bottled red wines, sealed with natural cork closures, and stored in a vertical upright position may develop spoilage by acetic acid bacteria. This spoilage is evident as a distinct deposit of bacterial biofilm in the neck of the bottle at the interface of the wine and the headspace of air, and is accompanied with vinegar, sherry, bruised apple, nutty, and solvent like off-aromas, depending on the degree of spoilage. This review focuses on the wine associated AAB species, the aroma and flavour changes in wine due to AAB metabolism, discusses the importance of oxygen ingress into the bottle and presents a hypothesis for the mechanism of spoilage of bottled red wine.

Nitrogen is an essential plant nutrient, widely applied as N-fertilizer to improve yield of agriculturally important crops. An interesting alternative to avoid or reduce the use of N-fertilizers could be the exploitation of plant growth-promoting bacteria (PGPB), capable of enhancing growth and yield of many plant species, several of agronomic and ecological significance. PGPB belong to diverse genera, including Azospirillum, Azotobacter, Herbaspirillum, Bacillus, Burkholderia, Pseudomonas, Rhizobium, and Gluconacetobacter, among others. They are capable of promoting plant growth through different mechanisms including (in some cases), the biological nitrogen fixation (BNF), the enzymatic reduction of the atmospheric dinitrogen (N(2)) to ammonia, catalyzed by nitrogenase. Aerobic bacteria able to oxidize ethanol to acetic acid in neutral or acid media are candidates of belonging to the family Acetobacteraceae. At present, this family has been divided into ten genera: Acetobacter, Gluconacetobacter, Gluconobacter, Acidomonas, Asaia, Kozakia, Saccharibacter, Swaminathania, Neoasaia, and Granulibacter. Among them, only three genera include N(2)-fixing species: Gluconacetobacter, Swaminathania and Acetobacter. The first N(2)-fixing acetic acid bacterium (AAB) was described in Brazil. It was found inside tissues of the sugarcane plant, and first named as Acetobacter diazotrophicus, but then renamed as Gluconacetobacter diazotrophicus. Later, two new species within the genus Gluconacetobacter, associated to coffee plants, were described in Mexico: G. johannae and G. azotocaptans. A salt-tolerant bacterium named Swaminathania salitolerans was found associated to wild rice plants. Recently, N(2)-fixing Acetobacter peroxydans and Acetobacter nitrogenifigens, associated with rice plants and Kombucha tea, respectively, were described in India. In this paper, recent advances involving nitrogen-fixing AAB are presented. Their natural habitats, physiological and genetic aspects, as well as their association with different plants and contribution through BNF are described as an overview.

Acetic acid bacteria are used for industrial vinegar production because of their remarkable ability to oxidize ethanol and high resistance to acetic acid. Although several molecular machineries responsible for acetic acid resistance in acetic acid bacteria have been reported, the entire mechanism that confers acetic acid resistance has not been completely understood. One of the promising methods to elucidate the entire mechanism is global analysis of proteins responsive to acetic acid by two-dimensional gel electrophoresis. Recently, two proteins whose production was greatly enhanced by acetic acid in Acetobacter aceti were identified to be aconitase and a putative ABC-transporter, respectively; furthermore, overexpression or disruption of the genes encoding these proteins affected acetic acid resistance in A. aceti, indicating that these proteins are involved in acetic acid resistance. Overexpression of each gene increased acetic acid resistance in Acetobacter, which resulted in an improvement in the productivity of acetic acid fermentation. Taken together, the results of the proteomic analysis and those of previous studies indicate that acetic acid resistance in acetic acid bacteria is conferred by several mechanisms. These findings also provide a clue to breed a strain having high resistance to acetic acid for vinegar fermentation.

The influence of turning and environmental contamination on six spontaneous cocoa bean heap fermentations performed in Ghana was studied through a multiphasic approach, encompassing both microbiological (culture-dependent and culture-independent techniques) and metabolite target analyses. A sensory analysis of chocolate made from the fermented, dried beans was performed as well. Only four clusters were found among the isolates of acetic acid bacteria (AAB) identified: Acetobacter pasteurianus, Acetobacter ghanensis, Acetobacter senegalensis, and a potential new Acetobacter lovaniensis-like species. Two main clusters were identified among the lactic acid bacteria (LAB) isolated, namely, Lactobacillus plantarum and Lactobacillus fermentum. No differences in biodiversity of LAB and AAB were seen for fermentations carried out at the farm and factory sites, indicating the cocoa pod surfaces and not the general environment as the main inoculum for spontaneous cocoa bean heap fermentation. Turning of the heaps enhanced aeration and increased the relative population size of AAB and the production of acetic acid. This in turn gave a more sour taste to chocolate made from these beans. Bitterness was reduced through losses of polyphenols and alkaloids upon fermentation and cocoa bean processing.

Microbial asymmetric oxidation of 2-butyl-1,3-propanediol was investigated for an efficient synthesis of S- and R-enantiomers of 2-hydroxymethylhexanoic acid (2-HMHA). From an intensive survey of the stocked bacterial strains, Acetobacter pasteurianus IAM 12073 and Pseudomonas putida IFO 3738 were found to show the highest S- and R-2-HMHA-producing activity, respectively. Under optimized conditions, A. pasteurianus (351 mg dry cell weight) and P. putida (642 mg dry cell weight) cells produced 12.0 g l(-1) S-2-HMHA with 89% enantiomeric excess (e.e.) at 24 h of incubation and 5.1 g l(-1) R-2-HMHA with 94% e.e. at 35 h of incubation from 2-butyl-1,3-propanediol.

The presence of acetic acid bacteria populations on grape surfaces from several Chilean valleys is reported. The bacteria were analysed at both the species and the strain level by molecular methods such as RFLP-PCR 16S rRNA gene, RFLP-PCR ITS 16S-23S rRNA gene regions and Arbitrary Primed (AP) PCR. Our results show that there are limited numbers of species of acetic acid bacteria in the grapes and that there is a need for an enrichment medium before plating to recover the individual colonies. In the Northernmost region analysed, the major species recovered was a non-acetic acid bacteria, Stenotrophomonas maltophila. Following the North-South axis of Chilean valleys, the observed distribution of acetic acid bacteria was zonified: Acetobacter cerevisiae was only present in the North and Gluconobacter oxydans in the South. Both species were recovered together in only one location. The influence of the grape cultivar was negligible. Variability in strains was found to be high (more than 40%) for both Acetobacteraceae species.

The Ghanaian cocoa bean heap fermentation process was studied through a multiphasic approach, encompassing both microbiological and metabolite target analyses. A culture-dependent (plating and incubation, followed by repetitive-sequence-based PCR analyses of picked-up colonies) and culture-independent (denaturing gradient gel electrophoresis [DGGE] of 16S rRNA gene amplicons, PCR-DGGE) approach revealed a limited biodiversity and targeted population dynamics of both lactic acid bacteria (LAB) and acetic acid bacteria (AAB) during fermentation. Four main clusters were identified among the LAB isolated: Lactobacillus plantarum, Lactobacillus fermentum, Leuconostoc pseudomesenteroides, and Enterococcus casseliflavus. Other taxa encompassed, for instance, Weissella. Only four clusters were found among the AAB identified: Acetobacter pasteurianus, Acetobacter syzygii-like bacteria, and two small clusters of Acetobacter tropicalis-like bacteria. Particular strains of L. plantarum, L. fermentum, and A. pasteurianus, originating from the environment, were well adapted to the environmental conditions prevailing during Ghanaian cocoa bean heap fermentation and apparently played a significant role in the cocoa bean fermentation process. Yeasts produced ethanol from sugars, and LAB produced lactic acid, acetic acid, ethanol, and mannitol from sugars and/or citrate. Whereas L. plantarum strains were abundant in the beginning of the fermentation, L. fermentum strains converted fructose into mannitol upon prolonged fermentation. A. pasteurianus grew on ethanol, mannitol, and lactate and converted ethanol into acetic acid. A newly proposed Weissella sp., referred to as "Weissella ghanaensis," was detected through PCR-DGGE analysis in some of the fermentations and was only occasionally picked up through culture-based isolation. Two new species of Acetobacter were found as well, namely, the species tentatively named "Acetobacter senegalensis" (A. tropicalis-like) and "Acetobacter ghanaensis" (A. syzygii-like).

Bacteria belonging to the genus Acetobacter and Gluconobacter, and enzymes isolated from them, have been extensively used for biosensor construction in the last decade. Bacteria used as a biocatalyst are easy to prepare and use in amperometric biosensors. They contain multiple enzyme activities otherwise not available commercially. The range of compounds analyzable by Gluconobacter biosensors includes: mono- and poly-alcohols, multiple aldoses and ketoses, several disaccharides, triacylglycerols, and complex parameters like utilizable saccharides or biological O2 demand. Here, the recent trends in Gluconobacter biosensors and current practical applications are summarized.

Background: Lipopolysaccharide (LPS), a major component of the cell walls of Gram-negative bacteria, was one of the main components of Coley's vaccine and is known to have strong adjuvanticity. Though it is known that LPS exists in the digestive tract of organisms, the biological significance for the organism has not been clarified. In this study, the correlation between the structure and function of LPS was determined using acetic acid bacteria. These are Gram-negative bacteria consumed in human diets., Materials and Methods: Extracts were obtained from a strain of acetic acid bacteria which is used for producing vinegar. Determination of the LPS neutralizing activity was carried out by the Limulus test. Tumor necrosis factor (TNF) and nitric oxide (NO) production were then observed after the addition of the extracts to murine monocyte macrophages (RAW264. 7), with or without Polymyxin B. TNF production in peritoneal macrophages derived from LPS-low responsive mice (C3H/HeJ) was studied after the addition of extracts., Results: The extracts were shown to be positive only in LPS-specific Limulus test and were negative in the (1,3)-beta-D-glucan-specific Limulus test. Both extracts induced NO and TNF production in RAW264. 7 cells, but this was inhibited by the presence of Polymyxin B. TNF production was inhibited in peritoneal macrophages from LPS low-responsive mice (C3H/HeJ)., Conclusion: LPS with macrophage-activating activity is present in acetic acid bacteria, routinely consumed by humans.