I Nyoman P. Aryantha (1,2) and Ima Noor Puspitasari (1)
1Microbiology-Genetics-Cell Molecular Biology Division, School of Life Sciences and Technology
2Center for Life Sciences
Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132
Email : nyoman@sith.itb.ac.id
ABSTRACT
Microbial Fuel Cell (MFC) is an alternative bioenergy system to anticipate electricity energy crisis in the future. This system directly converts nitrogen feed into electricity using catalytic reaction of heterotrophic bacteria, Xanthomonas sp. The performance of this bacterium is tried to be improved through a mutation approach by gamma irradiation. The purpose of this research was to select the optimum gamma radiation dose for Xanthomonas sp. which can increase its electricity voltage generation in MFC system and to study changes in environmental factors that occurred in MFC system. Six doses of gamma radiation (0.1 - 0.6 KGy) were exposed to Xanthomonas sp. cell suspension in a physiological solution (NaCl 0.85%). The bacterial cells were then grown on agar plates for enumeration. The average amounts of survival colonies showed that the lowest radiation dose (0.1 KGy) resulted in the highest survival rate. The survival colonies from each dose were selected randomly into total 90 mutant candidates and grown in liquid glucose (2,3%)-urea (0,1%) medium. Mutant candidates were set up as anode component in a 300 mL “Zeclace” chamber and “Polyum” solution as cathode component in a 300 mL plastic chamber (Aryantha & Jamilah, 2009). The electrical voltage obtained by bacterial mutants after Gamma irradiation at 0.1; 0.2; 0.3; 0.4; 0.5 and 0.6 KGy were: 1.298, 1.271, 1.318, 1.280, 1.172 and 1.293 V, respectively. These results are higher from the voltage obtained by the wild type isolate (1.147 V). Mutant isolate of 0.6 KGy was chosen since it produces the highest voltage and also it is the highest doses of irradiation which is expected to be more stable mutant than the lower dose mutants. Isolate with the highest value of voltage was chosen, then its DNA was extracted for RAPD. The profile of RAPD used 4 primer universal which showed 29 polymorphic bands, OP-A04 (7 polymorphic bands), OP-C09 (8 polymorphic bands), OP-G11 (4 polymorphic bands), OP-T20 (10 polymorphic bands). The continous measurement of MFC system was being done for 120 h. The maximum value (1.487 V; 1.487 Å; 2.211 Watt) was reached at the age of 17 h, which is higher than wild type (1.408 V; 1.408 Å; 1,982 Watt). Biomass and electricity generation were depleted constantly afterwards with the decreasion of pH. This result suggests that random mutation through Gamma irradiation can improve the bacterial potency in generating electricity through MFC system, which is showed by RAPD profile and high electricity power of the mutant.
1Microbiology-Genetics-Cell Molecular Biology Division, School of Life Sciences and Technology
2Center for Life Sciences
Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132
Email : nyoman@sith.itb.ac.id
ABSTRACT
Microbial Fuel Cell (MFC) is an alternative bioenergy system to anticipate electricity energy crisis in the future. This system directly converts nitrogen feed into electricity using catalytic reaction of heterotrophic bacteria, Xanthomonas sp. The performance of this bacterium is tried to be improved through a mutation approach by gamma irradiation. The purpose of this research was to select the optimum gamma radiation dose for Xanthomonas sp. which can increase its electricity voltage generation in MFC system and to study changes in environmental factors that occurred in MFC system. Six doses of gamma radiation (0.1 - 0.6 KGy) were exposed to Xanthomonas sp. cell suspension in a physiological solution (NaCl 0.85%). The bacterial cells were then grown on agar plates for enumeration. The average amounts of survival colonies showed that the lowest radiation dose (0.1 KGy) resulted in the highest survival rate. The survival colonies from each dose were selected randomly into total 90 mutant candidates and grown in liquid glucose (2,3%)-urea (0,1%) medium. Mutant candidates were set up as anode component in a 300 mL “Zeclace” chamber and “Polyum” solution as cathode component in a 300 mL plastic chamber (Aryantha & Jamilah, 2009). The electrical voltage obtained by bacterial mutants after Gamma irradiation at 0.1; 0.2; 0.3; 0.4; 0.5 and 0.6 KGy were: 1.298, 1.271, 1.318, 1.280, 1.172 and 1.293 V, respectively. These results are higher from the voltage obtained by the wild type isolate (1.147 V). Mutant isolate of 0.6 KGy was chosen since it produces the highest voltage and also it is the highest doses of irradiation which is expected to be more stable mutant than the lower dose mutants. Isolate with the highest value of voltage was chosen, then its DNA was extracted for RAPD. The profile of RAPD used 4 primer universal which showed 29 polymorphic bands, OP-A04 (7 polymorphic bands), OP-C09 (8 polymorphic bands), OP-G11 (4 polymorphic bands), OP-T20 (10 polymorphic bands). The continous measurement of MFC system was being done for 120 h. The maximum value (1.487 V; 1.487 Å; 2.211 Watt) was reached at the age of 17 h, which is higher than wild type (1.408 V; 1.408 Å; 1,982 Watt). Biomass and electricity generation were depleted constantly afterwards with the decreasion of pH. This result suggests that random mutation through Gamma irradiation can improve the bacterial potency in generating electricity through MFC system, which is showed by RAPD profile and high electricity power of the mutant.
Keywords : microbial fuel cells (MFC), gamma irradiation, radiation dose, Xanthomonas sp., RAPD, electrical voltage
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4th International Conference on Mathematics and Natural Sciences (ICMNS), Bandung, 23-25 November 2010
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