Figure 3.9
61
Large-Scale Production of BNC
Figure 3.9
Outline.of.culture.pan.for.the.direct.filamentation.of.BNC..a,.sinker;.b,.roller;.c,.washing.pan;.
d,.wind.up.roller.developed.by.Sakairi.(Sakairi.et.al..1998).
They. devised. a. shallow. pan,. conserving. the. culture. medium. under. static.
conditions,.for.continuous.filamentation.of.a.thin.BNC.gel.(see.Figure 3.9)..
One.side.of.the.shallow.pan.was.curved.gently.to.permit.harvesting.of.the.
BNC. pellicle. through. a. narrow. mouth.. The. filament.obtained. was. wound.
slowly. on. an. attached. basket,. whereas. the. BNC. gel. was. stretched. in. a.
slightly.twisted.mode.on.the.in.situ.formability.of.BNC,.Klemm.et.al..(1999).
used.the.G. xylinus strain.DSM.14666.as.a.“cellulose.factory”.to.produce.BNC.
in.the.form.of.tubes..With.this.patented.matrix.technology.it.is.possible.to.
synthesize.cellulose.in.the.shape.of.hollow.bodies.of.different.length,.wall.
thickness,.and.inner.diameter.directly.in.the.culture.medium..The.resulting.
tube,.also.called.BASYC ® ,.has.an.inner.diameter.of.1–3.mm,.a.length.of.about.
5 mm,.and.a.wall.thickness.of.0.7.mm..These.parameters.make.the.resulting.
tubes.well.suited.for.microsurgical.applications.
Non-Static-Film Bioreactors
Non-static-film.bioreactors.without.agitation.by.a.stirrer.or.shaker,.but.with.
movement.by.discs,.belt.conveyors,.or.others.methods.were.used.in.the.production.of.BNC.by.Bungay.and.Serifica.(2000)..BNC.pellicles.were.obtained.
by.culturing.cellulose-producing.organisms.for.long.periods.of.time.under.
nonstatic.conditions.under.application.of.linear.conveyors.or.rotating.disks.
operated. in. fed-batch. mode.. In. the. first,. a. linear. conveyor. passes. through.
and.exits.the.culture.medium.contained.in.vessels.coated.by.a.BNC.gel.film,.
which.is.partially.dehydrated.(see.Figure 3.10,.right.panel)..The.gel.film.is.
abraded. afterward.. In. the. latter. reactor,. the. same. effect. is. obtained. using.
rotating.disks.instead.of.the.conveyor.(see.Figure 3.10,.left.panel)..These.bioreactors.provide.highly.hydrated.pellicular.and.film.forms.of.BNC.and.may.
lead.to.nonuniform.BNC.material.due.to.the.bundling.and.aggregation.of.
thin.layers.or.filaments..During.cultivation,.sugar.is.added.in.order.to.maintain.a.certain.level.of.sugar.concentration.in.the.reactor.during.the.course.of.
the.fermentation.
Later,. the. generation. of. BNC. on. rotating. rollers. or. discs. was. investigated.by.Krystynowicz.et.al..(2002)..A.specific.biofilm.of.cells.and.polymer.
61
Large-Scale Production of BNC
Figure 3.9
Outline.of.culture.pan.for.the.direct.filamentation.of.BNC..a,.sinker;.b,.roller;.c,.washing.pan;.
d,.wind.up.roller.developed.by.Sakairi.(Sakairi.et.al..1998).
They. devised. a. shallow. pan,. conserving. the. culture. medium. under. static.
conditions,.for.continuous.filamentation.of.a.thin.BNC.gel.(see.Figure 3.9)..
One.side.of.the.shallow.pan.was.curved.gently.to.permit.harvesting.of.the.
BNC. pellicle. through. a. narrow. mouth.. The. filament.obtained. was. wound.
slowly. on. an. attached. basket,. whereas. the. BNC. gel. was. stretched. in. a.
slightly.twisted.mode.on.the.in.situ.formability.of.BNC,.Klemm.et.al..(1999).
used.the.G. xylinus strain.DSM.14666.as.a.“cellulose.factory”.to.produce.BNC.
in.the.form.of.tubes..With.this.patented.matrix.technology.it.is.possible.to.
synthesize.cellulose.in.the.shape.of.hollow.bodies.of.different.length,.wall.
thickness,.and.inner.diameter.directly.in.the.culture.medium..The.resulting.
tube,.also.called.BASYC ® ,.has.an.inner.diameter.of.1–3.mm,.a.length.of.about.
5 mm,.and.a.wall.thickness.of.0.7.mm..These.parameters.make.the.resulting.
tubes.well.suited.for.microsurgical.applications.
Non-Static-Film Bioreactors
Non-static-film.bioreactors.without.agitation.by.a.stirrer.or.shaker,.but.with.
movement.by.discs,.belt.conveyors,.or.others.methods.were.used.in.the.production.of.BNC.by.Bungay.and.Serifica.(2000)..BNC.pellicles.were.obtained.
by.culturing.cellulose-producing.organisms.for.long.periods.of.time.under.
nonstatic.conditions.under.application.of.linear.conveyors.or.rotating.disks.
operated. in. fed-batch. mode.. In. the. first,. a. linear. conveyor. passes. through.
and.exits.the.culture.medium.contained.in.vessels.coated.by.a.BNC.gel.film,.
which.is.partially.dehydrated.(see.Figure 3.10,.right.panel)..The.gel.film.is.
abraded. afterward.. In. the. latter. reactor,. the. same. effect. is. obtained. using.
rotating.disks.instead.of.the.conveyor.(see.Figure 3.10,.left.panel)..These.bioreactors.provide.highly.hydrated.pellicular.and.film.forms.of.BNC.and.may.
lead.to.nonuniform.BNC.material.due.to.the.bundling.and.aggregation.of.
thin.layers.or.filaments..During.cultivation,.sugar.is.added.in.order.to.maintain.a.certain.level.of.sugar.concentration.in.the.reactor.during.the.course.of.
the.fermentation.
Later,. the. generation. of. BNC. on. rotating. rollers. or. discs. was. investigated.by.Krystynowicz.et.al..(2002)..A.specific.biofilm.of.cells.and.polymer.