Acetobacter xylinum Caracteristic
Classification
Bactiera; Protobcteria; Alphaproteobacteria; Rhodospirllales;
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 [1]. In nature A. xylinum is
found in soil and is commonly found on rotting fallen fruits. [3] It's exceptional ability to produce
cellulose has made it a common choice for researchers studying the biosynthesis
of cellulose [2]. As a model organism it is used to study
the mode by which cellulose is synthesized from glucose by bacteria like A.
xylinum and to explore A. xylinum's potential
industrial and textile applications. [4]
Genome structure
The complete genome for A. xylinum consists of a single
3136 kb circular chromosome as well as a number of plasmids which vary
depending on the specific strain. So far 3265 genes have been identified and
reported on NCBI with special attention to those involved in cellulose
biosynthesis [5]. The oporon for cellulose synthase has
been identified to contain three genes, acsAB, acsC and acs D. [2]
Cell structure, metabolism & life cycle
A. xylinum are gram-negative rods occurring
as individuals, pairs, chains or small clusters. When motile, flagella are
arranged peritrichously [6] 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. [2], [3] 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. [3]
Ecology
In nature A. xylinum in found in soil, sometimes in
symbiosis with plats such as sugarcane or coffe plants. [2] 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. [3] [4]
Applications
Beyond the lab, potential applications of A. xylinum's cellulose
producing properties are widespread and varied. In 2007 a proposal for the
potential application of A. xylinum as a "100%
biocompatable self-contructing protective packaging" won third place in
Bayer MaterialScience VisionWorks Award. This project titled BACS highlights
applications including moisturizing packaging for keeping food fresh and
creating custom grown packaging. The natural production and biodegradability of
the product make it more eco-friendly as well. [7] Other potential applications for A.
xylinum include paper making where it could be used to create stronger
paper without the need for wood. [8] Other applications include audio
components to create speaker membranes from microbial cellulose, wound care
using microbial cellulose as molded artificial arteries and skin, and as a drug
delivery agent due to microbial cellulose's ability to hold water. [4]
References
[1] Haigler. C.H., Weimer P.J. "Biosynthesis and
Biodegredation of Cellulose" CRC Press. 1991. p. 100
[2] University of Ottawa, "Acetobacter xylinum".
uOttawa IGEM. 2009
[3] Skinner P., Cannon R. "Acetobacter xylinum an
Inquiry into Cellulose Biosynthesis". The American Biology Teacher,
Vol. 62, No 6. 2000. p. 1
[8] Surma-Ślusarska B., Presler S., Danielewicz D.,
"Characteristics of Bacterial Cellulose Obtained from Acetobacter
Xylinum Culture for Application in Papermaking", FIBRES &
TEXTILES in Eastern Europe 2008, Vol. 16, No. 4 (69) pp. 108-111.
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