iron reducing bacteria capable of e

iron reducing bacteria capable of electricity generation in
MFCs can transfer electrons using self-produced nanowires
(Gorby et al., 2006; Reguera et al., 2005). It may therefore
be possible that the bacteria that produced electricity in the
current study also used nanowires, although cyclic voltammetry
cannot be used to detect the presence of nanowires
(Logan et al., 2006).
3.3. Breakdown intermediates during ethanol oxidation
Breakdown products in the head space and solution
were analyzed in two MFCs operated in diVerent modes.
Initially, both MFCs were operated in a normal closed circuit
mode. Once there was sustained power generation over
several cycles, the external circuit for one of these MFCs
was opened (shown at 2h; open circuit mode; Fig. 5) in
order to examine ethanol degradation in the absence of the
circuit for transferring electrons. The MFC operated with a
closed circuit produced 200mV (470; Fig 5A). Ethanol
degradation was more rapid in the MFC than in the reactor
with the disconnected circuit, although ethanol was eventually
completely degraded in both systems (Fig 5C). Ethanol
degradation resulted in the accumulation of 8% CO2 in the
reactor headspace (70ml of head space) after 140 h (Fig 5B)
for the MFC. CO2 production also occurred in the open circuit
reactor, but not until after 34 h and at a lower Wnal concentration
in the headspace (»3%). Methane (1–2%) was
found in the headspace of the open circuit reactor after
20 h, and remained constant over the operation period of
140 h. However, methane was not detected in the closed circuit
MFC (i.e. under conditions of electricity generation).
Acetate was produced in both reactors as a result of ethanol
degradation (Fig. 5D). Acetate was rapidly produced
in the closed circuit reactor while no acetate was observed
in the open circuit reactor for the Wrst 7 h of operation, even
though »0.4mM of ethanol was consumed (Fig. 5C). The
rapid appearance of acetate in the closed circuit MFC indicated
that electricity generation proceeded in a manner
related to ethanol degradation via acetate. However, the
production of acetate in the open circuit MFC suggests that
acetate production was also possible without electron
transfer to the anode, perhaps as a result of bacterial
metabolism sustained by oxygen that diVused into the
anode chamber through the membrane or using sulfate in
the medium. Acetaldehyde, which is produced by metal-catalyzed
reactions in ethanol fuel cells, was not detected.
When the circuit in the open circuit reactor was reconnected
after 28 days, the voltage again increased indicating
the bacteria in the bioWlm were still present and viable after
this long inactive period.
The high concentrations of acetate produced in the
MFC led us to wonder if electricity production occurred
only from acetate, and not from ethanol. The observation
that acetate was produced from ethanol, and the lack of
acetate accumulation in the medium at the end of a batch
test also indicates that electricity is produced from acetate.
When acetate was injected into an ethanol-acclimated
MFC, a rapid increase in voltage was observed within
30min (data not shown). This result indicates that the metabolic
pathway of the collective bacterial community using
ethanol also has the metabolic capability of acetate oxidation
with anode reduction. We further examined whether
acclimation of a MFC to only acetate would create conditions
that would readily allow ethanol degradation. We
therefore added ethanol into an acetate-acclimated MFC.
Power generation was slow to develop, requiring over 40 h
to reach a maximum voltage as compared to only 30 min
with an ethanol-enriched MFC (Fig. 6). The delay for a
voltage increase indicated that the bioWlm needed to acclimate
to ethanol likely due to the growth of diVerent bacteria,
based on relatively long times relative to that needed
for new enzyme expression. It also showed that an acetateacclimated
bioWlm had the capacity to acclimate to ethanol.
3.4. Single-chamber MFC using ethanol
In order to see if greater power densities could be produced
in a MFC using ethanol, two diVerent approaches
were examined for inoculating a single-chamber MFC:
Fig. 5. Characteristics of two-chamber MFCs operated in closed and open
circuit mode during degradation of ethanol: (A) voltage; (B) CO2 concentration
in the headspace; (C) ethanol; and (D) acetate concentration in the
liquid.
Time (hr)
0 50 100 150
Acetate (mM)
0.0
0.5
1.0
1.5
Ethanol (mM)
0.0
0.5
1.0
1.5
2.0
Head space CO2 (%)
0
5
10
Voltage (mV)
0
100
200
Closed circuit
Open circuit
in open circuit mode
in closed circuit mode A
B
C
D

ผลลัพธ์ (อังกฤษ) 1:

iron reducing bacteria capable of electricity generation inMFCs can transfer electrons using self-produced nanowires(Gorby et al., 2006; Reguera et al., 2005). It may thereforebe possible that the bacteria that produced electricity in thecurrent study also used nanowires, although cyclic voltammetrycannot be used to detect the presence of nanowires(Logan et al., 2006).3.3. Breakdown intermediates during ethanol oxidationBreakdown products in the head space and solutionwere analyzed in two MFCs operated in diVerent modes.Initially, both MFCs were operated in a normal closed circuitmode. Once there was sustained power generation overseveral cycles, the external circuit for one of these MFCswas opened (shown at 2h; open circuit mode; Fig. 5) inorder to examine ethanol degradation in the absence of thecircuit for transferring electrons. The MFC operated with aclosed circuit produced 200mV (470 ; Fig 5A). Ethanoldegradation was more rapid in the MFC than in the reactorwith the disconnected circuit, although ethanol was eventuallycompletely degraded in both systems (Fig 5C). Ethanoldegradation resulted in the accumulation of 8% CO2 in thereactor headspace (70ml of head space) after 140 h (Fig 5B)for the MFC. CO2 production also occurred in the open circuitreactor, but not until after 34 h and at a lower Wnal concentrationin the headspace (»3%). Methane (1–2%) wasfound in the headspace of the open circuit reactor after20 h, and remained constant over the operation period of140 h. However, methane was not detected in the closed circuitMFC (i.e. under conditions of electricity generation).Acetate was produced in both reactors as a result of ethanoldegradation (Fig. 5D). Acetate was rapidly producedin the closed circuit reactor while no acetate was observedin the open circuit reactor for the Wrst 7 h of operation, eventhough »0.4mM of ethanol was consumed (Fig. 5C). Therapid appearance of acetate in the closed circuit MFC indicatedthat electricity generation proceeded in a mannerrelated to ethanol degradation via acetate. However, theproduction of acetate in the open circuit MFC suggests thatacetate production was also possible without electrontransfer to the anode, perhaps as a result of bacterialmetabolism sustained by oxygen that diVused into theanode chamber through the membrane or using sulfate inthe medium. Acetaldehyde, which is produced by metal-catalyzedreactions in ethanol fuel cells, was not detected.When the circuit in the open circuit reactor was reconnectedafter 28 days, the voltage again increased indicatingthe bacteria in the bioWlm were still present and viable afterthis long inactive period.The high concentrations of acetate produced in theMFC led us to wonder if electricity production occurredonly from acetate, and not from ethanol. The observationthat acetate was produced from ethanol, and the lack ofacetate accumulation in the medium at the end of a batchtest also indicates that electricity is produced from acetate.When acetate was injected into an ethanol-acclimatedMFC, a rapid increase in voltage was observed within30min (data not shown). This result indicates that the metabolicpathway of the collective bacterial community usingethanol also has the metabolic capability of acetate oxidationwith anode reduction. We further examined whetheracclimation of a MFC to only acetate would create conditionsthat would readily allow ethanol degradation. Wetherefore added ethanol into an acetate-acclimated MFC.Power generation was slow to develop, requiring over 40 hto reach a maximum voltage as compared to only 30 minwith an ethanol-enriched MFC (Fig. 6). The delay for avoltage increase indicated that the bioWlm needed to acclimateto ethanol likely due to the growth of diVerent bacteria,based on relatively long times relative to that neededfor new enzyme expression. It also showed that an acetateacclimatedbioWlm had the capacity to acclimate to ethanol.3.4. Single-chamber MFC using ethanolIn order to see if greater power densities could be producedin a MFC using ethanol, two diVerent approacheswere examined for inoculating a single-chamber MFC:Fig. 5. Characteristics of two-chamber MFCs operated in closed and opencircuit mode during degradation of ethanol: (A) voltage; (B) CO2 concentrationin the headspace; (C) ethanol; and (D) acetate concentration in theliquid.Time (hr)00 50 100 150Acetate (mM)0.00.51.01.5Ethanol (mM)0.00.51.01.52.0Head space CO2 (%)0.5.10.Voltage (mV)0.100200Closed circuitOpen circuitin open circuit modein closed circuit mode ABCD

ผลลัพธ์ (อังกฤษ) 2:

Iron reducing bacteria Capable of Electricity Generation in
MFCs Can Transfer electrons using self-produced nanowires
(Gorby et al., 2006th; Reguera et al., the 2,005th). Therefore It May
be possible that the bacteria that produced Electricity in the
current Study also used nanowires, Although cyclic Voltammetry
Can not be used to detect the Presence of nanowires
(Logan et al., Two thousand and six).
3.3. Breakdown during ethanol oxidation intermediates
Average score Products in the head and Space Solution
in Two MFCs were analyzed in DiVerent operated modes.
Initially, both MFCs were operated in a Closed Circuit Normal
mode. Power Generation once there was sustained over
several Cycles, the external Circuit for one of these MFCs
was opened (shown at 2h; open Circuit mode; Fig. 5) in
Order to examine ethanol degradation in the absence of the
Circuit for transferring electrons. The MFC operated with a
Closed Circuit produced 200mV (470 ?; Fig 5A). Ethanol
Rapid degradation was more than in the MFC in the Reactor
with the Disconnected Circuit, Although ethanol was eventually
completely degraded in both Systems (Fig 5C). Ethanol
degradation resulted in the accumulation of CO2 in the 8%
Reactor Headspace (70ml head of Space) after 140 H (Fig 5B)
for the MFC. CO2 Production also occurred in the open Circuit
Reactor, but not until after 34 H and at a Lower Wnal concentration
in the Headspace ( »3%). Methane (1-2%) was
Found in the Circuit Reactor Headspace of the open after
20 H, and remained Operation Constant over the period of
140 H. However, was not detected methane in the Closed Circuit
MFC (IE under conditions of Electricity Generation).
Acetate was produced in both reactors as a Result of ethanol
degradation (Fig. 5D). Acetate was rapidly produced
in the Reactor Closed Circuit while no acetate was observed
in the open for the Wrst Circuit Reactor H 7 of Operation, even
though »0.4mm of ethanol was consumed (Fig. 5C). The
Rapid appearance of acetate in the Closed Circuit MFC indicated
that Electricity Generation proceeded in a manner
related to ethanol degradation via acetate. However, the
Production of acetate in the open Circuit MFC suggests that
acetate Production was also possible Without Electron
Transfer to the anode, perhaps as a Result of bacterial
metabolism sustained by Oxygen that DiVused Into the
anode Chamber Through the membrane or using sulfate in
the Medium. . Acetaldehyde, which is produced by Metal-catalyzed
reactions in ethanol fuel cells, was not detected.
When the Circuit in the open Circuit Reactor was reconnected
after 28 days, the Voltage Again Increased Indicating
the bacteria in the BioWlm were still present and viable after
this. long inactive period.
The High concentrations of acetate produced in the
US to MFC LED Wonder if occurred Electricity Production
from acetate only, and not from ethanol. The Observation
that acetate was produced from ethanol, and the Lack of
acetate accumulation in the Medium at the End of a Batch
Test also indicates that Electricity is produced from acetate.
When acetate was injected Into an ethanol-used
MFC, a Rapid increase in Voltage. was observed Within
30min (Data not shown). This indicates that the metabolic Result
of the Pathway Community Collective using bacterial
metabolic ethanol also has the capability of acetate oxidation
with anode Reduction. We further examined whether
acclimation of a MFC only to acetate would create conditions
that would readily Allow ethanol degradation. We
added Therefore Into an ethanol-acetate used MFC.
Slow to Develop Power Generation was, requiring over 40 H
to reach a maximum Voltage as compared to only 30 min
with an ethanol-enriched MFC (Fig. 6). The Delay for a
Voltage increase indicated that the BioWlm Needed to acclimate
to ethanol likely Due to the growth of bacteria DiVerent,
based on relatively long times Relative to that Needed
for New Expression enzyme. Also Showed that an Acetateacclimated
BioWlm had the capacity to acclimate to ethanol.
3.4. Single-Chamber MFC using ethanol
In Order to See if Power greater densities could be produced
in a MFC using ethanol, DiVerent Two approaches
were examined for inoculating a single-Chamber MFC:
Fig. 5. Characteristics of Two-Chamber MFCs operated in open and Closed
Circuit mode during degradation of ethanol: (A) Voltage; (B) CO2 concentration
in the Headspace; (C) ethanol; and (D) acetate concentration in the
Liquid.
Time (HR)
0 50 100 150
Acetate (mM)
0.0
0.5
1.0
1.5
Ethanol (mM)
0.0
0.5
1.0
1.5
2.0
Head Space CO2 (%)
0
5
10
Voltage (mV)
0
100.
200
Closed Circuit
Open Circuit
Circuit in open mode
in Closed Circuit mode A
B
C
D.

ผลลัพธ์ (อังกฤษ) 3:

Iron reducing bacteria capable of electricity generation in.MFCs can transfer electrons using self-produced nanowires.(Gorby et al, 2006; Reguera et al, 2005). It may therefore.Be possible that the bacteria that produced electricity in the.Current study also used nanowires although cyclic, voltammetry.Cannot be used to detect the presence of nanowires.(Logan et al, 2006).3.3. Breakdown intermediates during ethanol oxidation.Breakdown products in the head space and solution.Were analyzed in two MFCs operated in diVerent modes.Initially both MFCs, were operated in a normal closed circuit.Mode. Once there was sustained power generation over.Several cycles the external, circuit for one of these MFCs.Was opened (shown at 2h; open circuit mode; Fig. 5 in.)Order to examine ethanol degradation in the absence of the.Circuit for transferring electrons. The MFC operated with a.Closed circuit produced 200mV (470; Fig 5A). Ethanol.Degradation was more rapid in the MFC than in the reactor.With the disconnected circuit although ethanol, was eventually.Completely degraded in both systems (Fig 5C). Ethanol.Degradation resulted in the accumulation of 8% CO2 in the.Reactor headspace (70ml of head space) after 140 H (Fig 5B).For the MFC. CO2 production also occurred in the open circuit.Reactor but not, until after 34 h and at a lower Wnal concentration.In the headspace (1 3%). Methane (1 - 2% was.)Found in the headspace of the open circuit reactor after.20 h and remained, constant over the operation period of.140 H. However methane was, not detected in the closed circuit.MFC (i.e. Under conditions of electricity generation).Acetate was produced in both reactors as a result of ethanol.Degradation (Fig. 5D). Acetate was rapidly produced.In the closed circuit reactor while no acetate was observed.In the open circuit reactor for the Wrst 7 h, of operation even.Though - 0.4mM of ethanol was consumed (Fig. 5C). The.Rapid appearance of acetate in the closed circuit MFC indicated.That electricity generation proceeded in a manner.Related to ethanol degradation via acetate. However the,,Production of acetate in the open circuit MFC suggests that.Acetate production was also possible without electron.Transfer to, the anode perhaps as a result of bacterial.Metabolism sustained by oxygen that diVused into the.Anode chamber through the membrane or using sulfate in.The medium. Acetaldehyde which is, produced by metal-catalyzed.Reactions in ethanol fuel cells was not, detected.When the circuit in the open circuit reactor was reconnected.After 28 days the voltage, again increased indicating.The bacteria in the bioWlm were still present and viable after.This long inactive period.The high concentrations of acetate produced in the.MFC led us to wonder if electricity production occurred.Only, from acetate and not from ethanol. The observation.That acetate was produced from ethanol and the, lack of.Acetate accumulation in the medium at the end of a batch.Test also indicates that electricity is produced from acetate.When acetate was injected into an ethanol-acclimated.MFC a rapid, increase in voltage was observed within.30min (data not shown). This result indicates that the metabolic.Pathway of the collective bacterial community using.Ethanol also has the metabolic capability of acetate oxidation.With anode reduction. We further examined whether.Acclimation of a MFC to only acetate would create conditions.That would readily allow ethanol degradation. We.Therefore added ethanol into an acetate-acclimated MFC.Power generation was slow to develop requiring over, 40 h.To reach a maximum voltage as compared to only 30 min.With an ethanol-enriched MFC (Fig. 6). The delay for a.Voltage increase indicated that the bioWlm needed to acclimate.To ethanol likely due to the growth of, diVerent bacteriaBased on relatively long times relative to that needed.For new enzyme expression. It also showed that an acetateacclimated.BioWlm had the capacity to acclimate to ethanol.3.4. Single-chamber MFC using ethanol.In order to see if greater power densities could be produced.In a MFC using ethanol two diVerent, approaches.Were examined for inoculating a single - chamber MFC:Fig. 5. Characteristics of two-chamber MFCs operated in closed and open.Circuit mode during degradation of ethanol: (A) voltage; (B) CO2 concentration.In the headspace; (C) ethanol; and (D) acetate concentration in the.Liquid.Time (HR).0 50 100 150.Acetate (mM).0.0.0.5.1.0.1.5.Ethanol (mM).0.0.0.5.1.0.1.5.2.0.Head space CO2 (%).0.5.10.Voltage (mV).0.100.200.Closed circuit.Open circuit.In open circuit mode.In closed circuit mode A.B.C.D.