The Gram-negative bacterium Acetobacter xylinum assembles a cellulse ribbon composed of a number of microfibrils in the longitudinal axis of its envelope. The zone of ribbon assembly was investigated by freeze-etch electron microscopy. Freeze-etching revealed, beneath the cellulose ribbons, a linear array of pores on the lipopolysaccharide membrane. These pores have a rim diameter of 120--150 A...

Previous papers from this laboratory (King and Cheldelin, 1952, 1952a, 1954; Hauge et al., 1955, 1955a) have reported on the oxidation of carbohydrates in Acetobacter suboxydans. Neither resting nor disintegrated cells can oxidize acetate or other intermediates of the tricarboxylic acid cycle. These findings have recently been confirmed in another laboratory (Rao and Gunsalus, 1955). From the c...

The aim of this work was to assess the possibility of using native bacterial nanocellulose (BC) as a carrier for laccase immobilization. BC was synthesized by Gluconacetobacter xylinus, which was statically cultivated in a mannitol-based medium and was freeze-dried to form BC sponge after purification. For the first time, fungal laccase from Trametes versicolor was immobilized on the native nan...

The mechanism of the increased cell growth and cellulose production of Acetobacter xylinum subsp. sucrofermentans BPR3001E, a sulfaguanidine (SG)-resistant mutant, was investigated. We found that adding p-aminobenzoic acid (PABA) to cultures of the parent strain, BPR2001, led to increased levels of intracellular adenosine-related purine compounds and increased cellulose production. Furthermore,...

The action of cellulosomes from Clostridium thermocellum on model cellulose microfibrils from Acetobacter xylinum and cellulose microcrystals from Valonia ventricosa was investigated. The biodegradation of these substrates was followed by transmission electron microscopy, Fourier-transform IR spectroscopy and X-ray diffraction analysis, as a function of the extent of degradation. The cellulosom...

Bacterial cellulose (BC) has a range of structural and physicochemical properties that make it a particularly useful material for the culture of bacteria. We studied the growth of 14 genera of bacteria on BC substrates produced by Acetobacter xylinum and compared the results to growth on the commercially available biopolymers agar, gellan, and xanthan. We demonstrate that BC produces rates of b...

It has previously been shown that cell-free extracts of Acetobacter subozydans possess two pathways for the oxidation of sorbitol (1). In the presence of DPN,l fructose is produced; with TPN, sorbose is formed. The primary purpose of this paper is to describe the separation of these two dehydrogenases from each other. The DPN enzyme free from TPN activity has been concentrated about lBfold, whe...

A polyphasic approach was applied to characterize 35 G. diazotrophicus isolates obtained from sugarcane varieties cultivated in Brazil. The isolates were analyzed by phenotypic (use of different carbon sources) and genotypic tests (ARDRA and RISA-RFLP techniques). Variability among the isolates was observed in relation to the carbon source use preference. Glucose and sucrose were used by all is...

Microbial terminal oxidases are usually associated with particulate fractions in the cell. These fractions, however, are difficult to resolve into smaller active molecules that are suitable for enzymatic studies in vitro. This fact led Rittenberg (1) to propose that these particles are surrounded by a special membrane. The present paper will report a method of “solubilization”’ of particulate o...

The ability to solubilize insoluble inorganic phosphate compounds by Gluconacetobacter diazotrophicus was studied using different culture approaches. Qualitative plate assays using tricalcium phosphate as the sole P-source showed that G. diazotrophicus produced solubilization only when aldoses were used as the C-source. Extracellular aldose oxidation via a pyrroloquinoline quinone-linked glucos...