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Bacterial Cellulose
Introduction
A.variety.of.approaches.are.available.for.the.generation.of.bacterial.nanocellulose.(BNC),.ranging.from.batch,.to.fed-batch,.to.continuous.cultivation.
methods.applying.typical.bioreactors.as.well.as.several.specific.devices..The.
choice. of. a. cultivation. technique. depends. on. the. application. of. the. BNC.
material,.since.the.cellulose.supramolecular.structure.and.its.physical.and.
mechanical.properties.are.strictly.influenced.by.the.production.method.
In. 1886. A.. J.. Brown. observed. the. formation. of. a. gelatinous. mass. on. the.
solution. surface. during. vinegar. fermentation. (Brown. 1886).. The. responsible. microorganism. is. called. Gluconacetobacter. xylinus. according. to. today’s.
nomenclature.. In. addition,. in. the. mid-20th. century. Hestrin. and. Schramm.
(1954).began.with.the.description.of.basic.metabolic.processes.of.this.bacteria.
strain.and.ended.with.the.development.of.a.special.culture.medium.for.optimized.production.of.BNC.on.a.laboratory.scale,.whereas.D-glucose.is.used.
as.a.. carbon.source.and.bacto.peptone.as.well.as.yeast.extract.as.sources.of.
nitrogen.and.vitamins..Both.discoveries.are.important.fundamentals.for.the.
variety.of.all.BNC.production.methods.available.today.
After. elucidation. of. the. formation. of. BNC. and. its. underlying. metabolic.
processes,. this. Gram-negative. bacterium. was. initially. applied. as. a. model.
organism.for.studying.cellulose.synthesis.and.crystallization.as.well.as.its.
degradation.on.a.laboratory.scale.(Chen.and.Brown.1999;.Hirai.et.al..1997;.
Ross.et.al..1991;.Saxena.and.Brown.2001)..Based.on.this,.versatile.knowledge.
was.gained.about.the.biosynthesis.and.the.resulting.structure.(Colvin.et.al..
1957;.Correns.et.al..1972;.Gagnaire.and.Taravel.1975;.Takai.et.al..1975;.Zaar.
1979)..The.systematic.and.comprehensive.research.during.the.last.decades,.
aimed. at. a. detailed. understanding. of. the. bioprocess. of. BNC. generation,.
provides.an.essential.contribution.to.the.integration.of.white.biotechnological. methods. in. polysaccharide. chemistry. and. product. development. based.
on. nanocellulose,. with. its. special. properties.. According. to. these. findings,.
a broad.range.of.commercial.application.possibilities.and.the.immense.economic.potential.of.BNC.have.become.visible.(Czaja.et.al..2006).
In. order. to. extend. the. range. of. commercial. BNC. applications,. taking. also.
into.account.the.ongoing.development.of.novel.materials.based.on.BNC.with.
groundbreaking.new.features,.access.to.various.types.of.BNC.materials.with.
varying. supramolecular. structure. and. diverse. material. properties. became.
indispensable..For.this.purpose,.and.in.respect.to.a.potential.scale-up.to.a.future.
commercial. production. process,. different. types. of. cultivation. (see. Table 3.1).
partly.combined.with.in.situ.modifications.by.additives.or.supports.have.been.
established.during.the.last.20.years..At.this.time,.the.in.situ.formability.of.BNC.
displays.one.important.and.specific.advantage.compared.with.other.natural.
or.synthetic.polymers.such.as.plant.cellulose,.polylactic.acid,.or.polyethylene.
Depending.on.the.type.of.cultivation,.as.well.as.on.the.cultivation.conditions,.BNC.can.be.produced.in.different.forms.and.sizes.(e.g.,.flat.BNC.fleeces.