32
Bacterial Cellulose
implants.in.skin.treatment..Furthermore,.cellulose.produced.by.microorganisms.can.be.shaped.for.the.particular.application.in.the.production.process,.
for. example,. in. the. shape. of. cylinders. (White. and. Brown. 1989).. One. of. the.
first.production.methods.for.forming.BNC.into.various.shapes.with.G. xylinus.
was.described.and.patented.by.Roberts.et.al..(1986).(European.patent.number.0186495)..In.this.method.an.oxygen-permeable.polymer.is.used,.such.as.
polyvinyl.chloride.(PVC)..This.oxygen-permeable.polymer.is.in.contact.with.
. oxygen,.whereas.the.other.side.is.in.contact.with.the.liquid.phase,.including.
the. bacteria.. The. growth. is. performed. under. static. conditions;. for. the. production.of.hollow.tubes,.the.cultivation.medium.with.bacteria.is.transferred.
into.an.oxygen-permeable.polymer.tube.so.that.the.inner.surface.is.in.contact.
with.the.liquid.phase.and.the.outer.surface.of.the.polymer.tube.is.in.contact.
with.the.oxygen..Since.the.polymer.is.oxygen.permeable,.the.oxygen.diffuses.
through.the.tube.and.becomes.available.to.the.bacteria.in.the.liquid.phase.
In.1990.Yamanaka.et.al..developed.and.patented.a.method,.similar.to.that.
of.Roberts.et.al..(1986),.for.producing.long,.hollow.microbial.cellulose.by.culturing. Acetobacter xylinum. (renamed. G. xylinus by. Yamanaka). in. a. hollow,.
oxygen-permeable.container.composed.of.silicon,.cellophane,.etc..(European.
patent.application.EP0396344)..This.method.produced.a.cellulose.membrane.
with.a.thickness.of.0.01–20.mm..In.2001.Klemm.et.al..described.a.method.for.
production.of.tube-shaped.cellulose,.BASYC ® ,.for.microsurgery.with.the.use.
of.G. xylinus.(named.in.the.article.as.A. xylinum)..The.method.was.specially.
designed.for.microsurgery.applications.for.the.replacement.of.blood.vessels.
with.a.diameter.of.1–3.mm..The.artificial.graft.of.BNC.is.produced.between.
cylindrical.glass.tubes,.and.the.advantage.of.this.method,.compared.with.the.
Yamanaka.model,.is.that.the.texture.of.the.inner.surface.can.be.controlled..
The.cultivation.is.performed.under.static.conditions.with.Hestrin–Schramm.
cultivation. medium.. The. oxygen. is. supplied. via. a. second. opening. to. the.
air.space.in.the.bioreactor..The.method.is.further.described.in.their.patent.
(U.S. patent.WO2001061026).
Tube Bioreactor
Another.type.of.bioreactor.used.for.the.production.of.artificial.blood.vessels.
as.well.as.for.the.production.of.microporous.scaffolds.for.bone.regeneration.
(Bäckdahl.et.al..2008;.Zaborowska.et.al..2010).was.developed.by.Paul.Gatenholm.
et.al..(2010).(U.S..patent.application.20100042197)..In.this.bioreactor.a.silicone.
tube.is.used.as.a.support.and.oxygen.supply.for.G. xylinus. Since.the.bacteria.are.
obligate.aerobes,.they.are.attracted.to.the.silicon.tube,.where.they.start.to.grow.
and.produce.cellulose.around.the.silicone.tube,.forming.a.tube-shaped.cellulose.vessel..The.cellulose.is.produced.at.the.outer.surface.of.the.silicone.tube..
The.rate.of.oxygen.supplied.into.the.. bioreactor.can.be.controlled.with.the.use.
of.silicone.tubing.in.a.glass.tube..The.BNC.tube.produced.has.high.mechanical.
resistance.and.high.burst.pressure.(U.S. patent. .application.20100042197)..This.
type.of.bioreactor.is.here.referred.to.as.“tube.bioreactor”.(Figure 2.6).
Bacterial Cellulose
implants.in.skin.treatment..Furthermore,.cellulose.produced.by.microorganisms.can.be.shaped.for.the.particular.application.in.the.production.process,.
for. example,. in. the. shape. of. cylinders. (White. and. Brown. 1989).. One. of. the.
first.production.methods.for.forming.BNC.into.various.shapes.with.G. xylinus.
was.described.and.patented.by.Roberts.et.al..(1986).(European.patent.number.0186495)..In.this.method.an.oxygen-permeable.polymer.is.used,.such.as.
polyvinyl.chloride.(PVC)..This.oxygen-permeable.polymer.is.in.contact.with.
. oxygen,.whereas.the.other.side.is.in.contact.with.the.liquid.phase,.including.
the. bacteria.. The. growth. is. performed. under. static. conditions;. for. the. production.of.hollow.tubes,.the.cultivation.medium.with.bacteria.is.transferred.
into.an.oxygen-permeable.polymer.tube.so.that.the.inner.surface.is.in.contact.
with.the.liquid.phase.and.the.outer.surface.of.the.polymer.tube.is.in.contact.
with.the.oxygen..Since.the.polymer.is.oxygen.permeable,.the.oxygen.diffuses.
through.the.tube.and.becomes.available.to.the.bacteria.in.the.liquid.phase.
In.1990.Yamanaka.et.al..developed.and.patented.a.method,.similar.to.that.
of.Roberts.et.al..(1986),.for.producing.long,.hollow.microbial.cellulose.by.culturing. Acetobacter xylinum. (renamed. G. xylinus by. Yamanaka). in. a. hollow,.
oxygen-permeable.container.composed.of.silicon,.cellophane,.etc..(European.
patent.application.EP0396344)..This.method.produced.a.cellulose.membrane.
with.a.thickness.of.0.01–20.mm..In.2001.Klemm.et.al..described.a.method.for.
production.of.tube-shaped.cellulose,.BASYC ® ,.for.microsurgery.with.the.use.
of.G. xylinus.(named.in.the.article.as.A. xylinum)..The.method.was.specially.
designed.for.microsurgery.applications.for.the.replacement.of.blood.vessels.
with.a.diameter.of.1–3.mm..The.artificial.graft.of.BNC.is.produced.between.
cylindrical.glass.tubes,.and.the.advantage.of.this.method,.compared.with.the.
Yamanaka.model,.is.that.the.texture.of.the.inner.surface.can.be.controlled..
The.cultivation.is.performed.under.static.conditions.with.Hestrin–Schramm.
cultivation. medium.. The. oxygen. is. supplied. via. a. second. opening. to. the.
air.space.in.the.bioreactor..The.method.is.further.described.in.their.patent.
(U.S. patent.WO2001061026).
Tube Bioreactor
Another.type.of.bioreactor.used.for.the.production.of.artificial.blood.vessels.
as.well.as.for.the.production.of.microporous.scaffolds.for.bone.regeneration.
(Bäckdahl.et.al..2008;.Zaborowska.et.al..2010).was.developed.by.Paul.Gatenholm.
et.al..(2010).(U.S..patent.application.20100042197)..In.this.bioreactor.a.silicone.
tube.is.used.as.a.support.and.oxygen.supply.for.G. xylinus. Since.the.bacteria.are.
obligate.aerobes,.they.are.attracted.to.the.silicon.tube,.where.they.start.to.grow.
and.produce.cellulose.around.the.silicone.tube,.forming.a.tube-shaped.cellulose.vessel..The.cellulose.is.produced.at.the.outer.surface.of.the.silicone.tube..
The.rate.of.oxygen.supplied.into.the.. bioreactor.can.be.controlled.with.the.use.
of.silicone.tubing.in.a.glass.tube..The.BNC.tube.produced.has.high.mechanical.
resistance.and.high.burst.pressure.(U.S. patent. .application.20100042197)..This.
type.of.bioreactor.is.here.referred.to.as.“tube.bioreactor”.(Figure 2.6).