Acetobacter Methanolicus MB Research Articles

Structure of the Acetobacter methanolicus MB 129 capsular polysaccharide, and of oligosaccharides resulting from degradation by bacteriophage Acm7

The capsular polysaccharide of Acetobacter methanolicus MB 129 consists of d-Glc, d-Gal, l-Rha, and l-glyceric acid in the molar ratios 1:1:1:0.3. Periodate oxidation, methylation analysis, solvolysis with HF, and detailed 1H and 13C NMR analysis resulted in the structure of the repeating unit shown below. ▪ Bacteriophage Acm7-associated endo-α- l-rhamnopyranoside hydrolase depolymerizes the CPS even in the presence of the O-acyl group, to give the respective hexa-, nona-, and dodeca-saccharides.

Structure of the capsular polysaccharide and the O-side-chain of the lipopolysaccharide from Acetobacter methanolicus MB 70, and of oligosaccharides resulting from their degradation by the bacteriophage Acm6

Acetobacter methanolicus MB 70 was shown to be related to the type strain of this species MB 58/4 (IMET 10945)having the same galactan → 2)-β- d-Gal f-(1 → 3)-β- d-Gal p-(1 → as the capsular polysaccharide (CPS) and the O-side-chain of the lipopolysaccharide (LPS). Additionally, a glucan built up of the disaccharide repeating unit → 6)α- d-Glc p-(1 → 2)-α- d-Glc p-(1 → was identified in strain MB 70. In the CPS, the polymers were present in the ratio ∼ 1:1, whereas the glucan preponderated in the LPS. Bacteriophage Acm6 specific to A. methanolicus MB 70 hydrolysed selectively the glucan component of both CPS and LPS. Structural elucidation of the resulting oligosaccharides led to the identification of the phage-associated depolymerase as an endo-α-(1 → 6)- d-glucopyranoside hydrolase.

Structure of the capsular polysaccharide and the O-side-chain of the lipopolysaccharide from Acetobacter methanolicus MB 135 (IMET 11402)

Structure of the capsular polysaccharide and the O-side-chain of the lipopolysaccharide from Acetobacter methanolicus MB 135 (IMET 11402)

Structure of the capsular polysaccharide and the O-side-chain of the lipopolysaccharide from Acetobacter methanolicus MB 58 (IMET B346)

Structure of the capsular polysaccharide and the O-side-chain of the lipopolysaccharide from Acetobacter methanolicus MB 58 (IMET B346)

Structure of the capsular polysaccharide and the O-side-chain of the lipopolysaccharide from Acetobacter methanolicus MB 58 (IMET B346)

Structure of the capsular polysaccharide and the O-side-chain of the lipopolysaccharide from Acetobacter methanolicus MB 58 (IMET B346)

Phage Acm1-mediated transduction in the facultatively methanol-utilizing Acetobacter methanolicus MB 58/4.

Phage Acm1, generally virulent for the acidophilic facultatively methanol-utilizing strain of Acetobacter methanolicus MB 58/4, is also capable of lysogenizing its host strain at a low rate. Using amino acid-auxotrophic mutants of A. methanolicus MB 58/4 as recipient strains, transduction of His, Leu and Tyr markers could be demonstrated in this system. The ability to prepare transducing lysates by propagation of phage Acm1 on the prototrophic donor strain A. methanolicus MB 58/4, the transduction of three different markers as well as the efficiency of transduction, and the occurrence of permutations in the phage genome indicate that phage Acm1 mediates generalized transduction. Phage Acm1 might be a useful tool in genetic studies of methylotrophic A. methanolicus.

Optimization of gluconic acid synthesis by removing limitations and inhibitions

AbstractThe optimization task was performed using the gluconic acid synthesis by the Acetobacter methanolicusMB 58 strain. The microorganisms were grown continuously on methanol as the growth substrate. After finishing the growth process by the deficiency of N and P, the gluconic acid synthesis was started by adding glucose. The synthesis process was performed continuously. The oxygen transfer rate depended on the gluconic acid concentration. During the growth process, the oxygen transfer rate reached a value of about 13 g O2 · kg−1 · h−1using a 30‐l glass fermenter equipped with a 6 blade stirrer and fully baffled. This rate declined to a value of between 2 and 5 g O2 · kg−1 · h−1 in the presence of gluconic acid concentrations above 150 g gluconic acid · kg−1medium. The yield (g gluconic acid · g−1glucose) depended on the gluconic acid concentration and amounted to y = 0.7 in relation to 150 g gluconic acid · kg−1medium and y = 0.8 in relation to 200 g · kg−1medium, respectively. The fermenters were coupled with ultrafiltration moduls (Fa. ROMICON and Fa. SARTORIUS). The biomass concentrations amounted from 5 to 40 g dry mass kg−1medium. The ultrafiltration modules retained the biomass within the fermentation system. A glucose solution (30 to 50 weight percent glucose) was continuously dosed into the fermenter. The retention time was chosen between 2 and 30 h. The gluconic acid synthesis rate reached values of up to 32 g gluconic acid · kg−1 · h−1. Within a range of up to 250 g gluconic acid · kg−1medium, the acid concentration had no influence on the enzyme activity.

Structure of the capsular polysaccharide and the O-side-chain of the lipopolysaccharide from Acetobacter methanolicus MB 135 (IMET 11402)

Structure of the capsular polysaccharide and the O-side-chain of the lipopolysaccharide from Acetobacter methanolicus MB 135 (IMET 11402)

Structure of the capsular polysaccharide and the O-side-chain of the lipopolysaccharide from Acetobacter methanolicus MB 70, and of oligosaccharides resulting from their degradation by the bacteriophage Acm6

Structure of the capsular polysaccharide and the O-side-chain of the lipopolysaccharide from Acetobacter methanolicus MB 70, and of oligosaccharides resulting from their degradation by the bacteriophage Acm6

Isolation of auxotrophic mutants from acetobacter methanolicus MB 58

AbstractThe lysine content of the biomass of the acidophilic facultatively methylotrophic bacterium Acetobacter methanolicus MB 58 was increased by genetic manipulations.A homoserine auxotroph, MB 58.196, and a threonine auxotroph, MB 58.195, were obtained from Acetobacter methanolicus MB 58 by N‐methyl‐N′‐nitro‐N‐nitrosoguanidine treatment.Investigations of enzyme activities revealed that the homoserine auxotroph lacks homoserine dehydrogenase activity, and the threonine auxotroph lacks homoserine kinase activity.Concerning the lysine‐producing ability, only the homoserine auxotrophic mutant accumulates lysine in the intracellular pool. The intracellular lysine content of this mutant was increased 40‐fold.An excretion of amino acids into the medium was not detected. A homoserine resistant mutant, MB 58.196.10, isolated from MB 58.196 by UV‐irradiation, was able to excrete lysine. About 95% of free lysine were found in the culture medium. Altogether, the free lysine concentration was increased 800‐fold in comparison to the wild‐type strain.By these genetic manipulations the total lysine concentration of MB 58.196 was increased to 2.7% and of MB 58.196.10 to 56% in comparison to the wild‐type strain.

Structure of the capsular polysaccharide and the O-side- chain of the lipopolysaccharide from Acetabacter methanolicus MB [formula omitted] (IMET (10945), and of oligosaccharides resulting from their degradation by the bacteriophage Acml

The capsular polysaccharide (CPS) and the O-side-chain of the lipopolysaccharide (LPS) of Acetobacter methanolicus MB 58 4 (IMET 10945) have been shown to contain the same disaccharide repeating unit, namely, → 2)-β- d-Gal f-(1 → 3)-β- d-Gal p-(1 →. Degradation of the CPS and the LPS with the bacteriophage Acml gave fragments built up of 1–5 repeating units; the octasaccharide preponderated. The phage-associated depolymerase proved to be a β- d-galactofuranoside hydrolase.

Mutagenesis ofAcetobacter methanolicus MB58 with the transposon Tn5

Transposon mutagenesis was applied to the isolation of mutants of the facultatively methylotrophic Acetobacter methanolicus MB 58. The transposon Tn5 (pSU2011) was transferred from Escherichia coli SM 10 by means of conjugation to Acetobacter methanolicus MB 58. Four out of 1850 stable Km-resistant transconjugants were identified that were formaldehyde sensitive and failed to grow on methanol.

Construction of a promoter‐probe vector for the methanol‐utilizing bacterium acetobacter methanolicus MB 58

AbstractWe report here the construction of a promoter‐probe vector, pRS2, which can be utilized in either Acetobacter methanolicus MB 58 or Escherichia coli due to the presence of broad‐host‐range replicon RSF 1010. The vector provides several unique restriction sites for promoter cloning as well as resistance markers for the selection of transformants. The promoter‐probe vector was constructed by inserting an EcoRI‐SalI‐polylinker fragment of pUC 19 into EcoRI/SalI digested pMK 16. The resulting plasmid, pRS1, was cloned into the unique EcoRI site of the broad‐host‐range plasmid RSF 1010.The vector was used to clone promoter‐containing sequences derived from the A. methanolicus MB 58 chromosome as well as the E. coli lac‐promoter.

Biochemical characterization of mutants of the facultatively ribulose monophosphate type methylotroph Acetobacter methanolicus MB 58 defective in C1 metabolism

Summary 18 methanol negative mutants of Acetobacter methanolicus MB 58 induced by MNNG or UV light were tested for enzymes of the linear and the cyclic dissimilatory sequence of formaldehyde as well as of phosphofructokinase. Most of the mutants are pleiotrophic ones. The highest proportion of defects was found in C1 regulated methanol dehydrogenase and in constitutive formaldehyde dehydrogenase activity. The cytochrome c deficiency was always combined with that of the methanol dehydrogenase. Formate dehydrogenase was only absent in one pleiotrophic mutant. In none of the heterotrophically grown mutants any enzyme of the dissimilatory RuMP cycle as well as phosphofructokinase were defective. Hexulose-6-phosphate isomerase could not be further induced by methanol in 3 methanol oxidation positive mutants indicating the existance of isoenzymes. No enzyme lesion was detected in 2 mutants which should be defective in other assimilatory enzymes.

The tricarboxy acid cycle in Acetobacter methanolicus

AbstractThe acidophilic methylotrophic Acetobacter methanolicus MB 58 possesses a complete set of TCA cycle enzymes. As in neutrophilic methylotrophs, during growth on C1‐compounds the cycle in acidophilic methylotrophs does not work to yield energy. This is also true for chemoheterotrophic growth of Acetobacter methanolicus. However, in the non‐methylotrophic Acetobacter pasteurianus when grown on glycerol, the citric acid cycle seems to operate to yield energy.