Mr. Acetobacter is……

Nata Acetobacter is….

Classification

Bacteria; Protobacteria; Alphaproteobacteria; Rhodospiralles; Acetobacteraceae; Gluconacetobacter; Acetobacter xylinum

Other Names

Gluconoacetobacter xylinus

Description and significance

Acetobacter xylinum is a non-pathogenic mesophile identified by A.J Brown in 1886 due to its ability to produce cellulose.  In nature A. xylinum is found in soil and is commonly found on rotting fallen fruits.  It’s exceptional ability to produce cellulose has made it a common choice for researchers studying the biosynthesis of cellulose.

Cell structure, metabolism & life cycle

A. xylinum are gram-negative rods occurring as individuals, pairs, chains or small clusters.  Cellulase synthase is secreted at pores arranged longitudinally along the cell allowing A. xylinum create a floating matrix of cellulose. A. xylinum is an obligate aerobe which metabolizes primarily glucose which it uses in cellulose synthesis. The floating matrix allows the cells to rise to the surface of a media where oxygen is abundant. The pathway for cellulose synthesis are as follows Glucose (glucokinase), Glucose-6-Phosphate (phosphoglucomutase), Glucose-1-Phosphate (UDP-glucose pyrophosphorylase), UDP-Glucose (cellulose synthase), Cellulose.

Ecology

In nature A. xylinum in found in soil, sometimes in symbiosis with plats such as sugarcane or coffe plants. A. xylinum’s ideal growth conditions are at a pH between 5 and 6.8 at 30˚C in a complex media consisting of primarily glucose but other carbon sources can be used even in the production of cellulose.

Applications

A. xylinum can be isolated from the rotten fruit, vegetables and fermented coconut water.  Many strains of A. xylinum is capable of producing cellulose with various sources of sugar such as glucose, sucrose, fructose, invert sugar, ethanol and glycerol.   A. xylinum is able to grow at a pH of about 3.5 although generally the development of cellulose occurred in range pH 4.0 to 5.0.

A. xylinum is usually maintained in slanted tomato medium agar. 200 g fresh tomatoes are boiled in 500 ml distilled water for 30 minutes. The results are then filtered and mixed with 1 g yeast extract, 50 g sucrose, 2.5 g peptone and 20 g agar. Volume then made into a 1000 ml with water and sterilized at 121 C for 15 minutes.  A. xylinum was grown by streaking on agar and incubated at 30C for 4 days. Preparation of nata starter Acetobacter xylinum which has grown on agar slanted medium was inoculated in sterile glucose in each liter contains 20 g of yeast extract 5 g, peptone 5 g and 2.7 g K2HPO4.  pH is adjusted to 4.2 using acetic acid.  Incubation performed for 7 days at 30 C.

Coconut Milk as medium boiled for 3 minutes and 10% sucrose, pH is adjusted to 4.2 using glacial acetic acid.  Added nata starter 20%, the container is then covered with filter cloth and incubation for 15-20 days.  Harvested Nata Sheet formed nata taken and washed repeatedly to remove the acid acetate and cut into cubes. Pieces of the cube soaked in water for 24 hours with periodically changing water until the acid smell disappeared. And ready to be mixed or consumed by various processing methods.

INACO regards!!!

 

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