Bacterial cellulose is
an exopolysaccharide produced by different species of bacteria like
Acetobacter, Aerobacter, Salmonella, Rhizobium,Sarcina, Achromobacter and
Azotobacter; Acetobacter xylinus being most widely studied strain. Structurally,
bacterial cellulose comprises of glucose units linked by 1 to 4 beta
glycosidic linkages.These nanofibrils then aggregate to form moicrofibrils which
crosslink with each other to form a 3D
structure of considerable mechanical strength.
One of the greatest advantages
of bacterial cellulose is that it is purely cellulose and does not contain
lignin or hemicelluloses as is the case with plant cellulose. Bacterial
cellulose produced by the micro-organism depends upon the culture conditions.
Cultures grown under static conditions tend to produce smooth and uniform cellulose
while those under agitated conditions usually form spheres and filaments. These
differences in structure as well as the water holding and gelling properties of
the bacterial cellulose along with its biodegradability and mechanical strength
have opened avenues for its use in food, pharmaceutical and other industries.
Nata
de pina and Nata de coco are traditional delicacies of the Philippines, and
they are nothing but bacterial cellulose! Nata de coco is the cellulose
produced when the bacterium grows on coconut milk while the cellulose is called
nata de pina when the bacterium grows on pineapple juice or pineapple waste. It is being used in fruit beverages to provide
a mouthfeel and different sensorial experience.
It
has shown to act as a stabilizing and suspending agent.
Addition of bacterial
cellulose to icecream helped retain the structure of icecream for an hour once
it was out of the freezer. Addition of bacterial cellulose to chocolate drinks
has shown to prevent the precipitation of cocoa solids thus giving a homogenous
beverage.
Bacterial
cellulose in combination with monascus fungi has the potential to form a class
of seafood imitators. The monascus fungi imparts color to the combination but
no taste while the water holding and gel forming capacities of cellulose give
it a texture. It also provides
high fiber content, limited calories and healthy nutrients.
Bacterial
cellulose has been used as a fat replacer in meatballs and is an approved fat
replacer for surimi products. Preliminary studies have shown bacterial
cellulose to lower the cholesterol level in
vivo and hence it is also being used to produce low cholesterol products.
Apart from this, it has also been used in active packaging in the form of antimicrobial
films as well as making edible films.
Apart
from food, bacterial cellulose is also widely used in the pharmaceutical
industry specially as scaffold for tissue engineering. It is also used in
manufacturing drug release systems, and as replacement for skin tissue,
cartilage and cornea. Biofill™ and Gengiflex™ are bacterial cellulose products
with applications in surgery and dental implants.
Its
not just the food and medical fields where bacterial cellulose finds application.
It is also employed in cosmetics(as light scatterer in sunscreen),
paper-making, optics(as flexible display screens for electronic devices)and
acoustics(membranes for loudspeakers).
Reference:
Zhijun
Shi et al, Utilization of Bacterial
Cellulose in Food, Food Hydrocolloids,
35 (2014) 539-545
Keshk,
Bacterial Cellulose production and its Industrial Applications, J
Bioprocess Biotechniq, (2014) 4(2)
Further
reading:
