The study describes cultivation of Dunaliella salina at the saline cathode in a Photosynthetic Microbial Fuel Cell (PMFC). The alga was isolated from Salt Lake Sambhar, Rajasthan, India, and identified using 18S rDNA sequencing analysis. The alga growth in PMFC was tested at 0.5 M to 1.5 M sodium chloride. The highest power and current density were obtained at 0.5 M NaCl with the values of 213.38 mW m−2 and 1020.5 mA m−2, respectively. The specific growth rate of algae was 0.4 day−1 with 566 mg/L lipids and 348.9 ± 25.6 μg/mL of glycerol content at 0.5 M PMFC. The PMFC operating at 1.0 M NaCl led to high β-carotene production (24.42 ± 1.8 μg/100 mg). The salinity in natural water resources makes it difficult to apply them in bioprocesses. This study establishes the utility of D. salina in saline water-based PMFC for the generation of power and high-value Dunaliella biomass.
Performance evaluation of a photosynthetic microbial fuel cell (PMFC) using Chlamydomonas reinhardtii at cathode
July 06, 2021
This study reports the use of Chlamydomonas reinhardtii at the cathode in a photosynthetic microbial fuel cell (PMFC). The PMFC produced power and current density of 15.21 W m-3 and 39 A m-3, respectively. The specific growth rate of algae culture at the cathode was 0.284 day-1. The system achieved COD removal at 73.30% with a Coulombic efficiency of 9.068 %. The usability of algae biomass was assessed in terms of its total phenol content (157.69 mg GAE/g algae DW), antioxidant activity (IC50 = 67.07 µg/ml), total Chlorophyll (18.95 mg/g), total Carotenoids (2.40 mg/g), and antibacterial properties against known pathogens. Overall, the study's findings suggested that C. reinhardtii supports high power output from a PMFC and is highly resourceful in terms of value-added products.
Microbial community modulates electrochemical performance and denitrification rate in a biocathodic autotrophic and heterotrophic denitrifying microbial fuel cell
Jan 1, 2019
A comparison of autotrophic (AD) and heterotrophic (HD) cathodic denitrification in a Microbial Fuel Cell (MFC) was made in this study. Denitrifying microbial consortia were developed from cow manure and soil and acclimatized under AD and HD conditions. The AD MFC supported the power output of 4.45 W m− 3 while removing nitrate nitrogen (N O 3--N) at the rate of 0.118 kg N O 3--N m− 3 d− 1. Significant power output (3.02 W m− 3) and nitrate removal rate (2.06 kg N O 3--N m− 3 d− 1) were achieved in HD MFC. Further, 16S rDNA based community analysis revealed higher diversity in HDMFC. The genus Thauera and Pseudomonas were predominant in ADMFC while genus Klebsiella and Alkaliphilus were abundant in HDMFC. The abundance of the denitrifying genes namely narG, nirS, and nosZ were assessed with the help of quantitative PCR and presence of all the genes in both the conditions ensured
Performance evaluation of algae assisted microbial fuel cell under outdoor conditions
April 19, 2020
This study reports for the first time an operation of an outdoor algae assisted Microbial Fuel Cell (MFC). The MFC (10 L) comprised of low-cost materials like rock phosphate blended clayware & low-density polyethylene bags as anodic & cathodic chamber respectively. Algae biomass after lipid extraction at 2 g/l served as electron donor at the anode. Chlorella vulgaris at cathode provided oxygen as electron acceptor and served as lipid source. The MFCs performed well in all aspects namely energy recovery, algae productivity, and cost of operation. The 5% RP-MFCs gave 0.307 kg/m3d algal productivity, 0.09 kg/m3d lipid productivity, and 11.5318 kWh/m3 of net energy recovery (NER). Rock phosphate served as a slow and constant source of phosphorus supporting algae growth. Proteobacteria (45.14%) were the dominant phyla while Alicyliphilus (5.46%) and Dechloromonas (4.74%) were the dominant genera at the anode. The estimated cost of the system was $11.225 only.
Assessing oil accumulation in the oleaginous yeast Cystobasidium oligophagum JRC1 using dairy waste cheese whey as a substrate
May 1, 2019
This study assesses the potential for the lipid production by the oleaginous yeast Cystobasidium oligophagum JRC1 using dairy industry waste cheese whey as a substrate. Cheese whey was used either untreated (UCW) or deproteinized (DCW) at different concentrations (25–100%) to serve as the carbon and energy source. Both UCW and DCW supported high biomass and lipid productivities. The biomass productivity of 0.076 ± 0.0004 and 0.124 ± 0.0021 g/L h, lipid productivity of 0.0335 ± 0.0004 and 0.0272 ± 0.0008 g/L h, and the lipid content of 44.12 ± 0.84 and 21.79 ± 1.00% were achieved for 100% DCW and UCW, respectively. The soluble chemical oxygen demand (sCOD) removal rate was 8.049 ± 0.198 and 10.61 ± 0.0165 g/L day (84.91 ± 0.155 and 86.82 ± 0.067% removal) for 100% DCW and UCW, respectively. Fatty acid methyl ester (FAME) composition obtained
Microbial Fuel Cell for simultaneous removal of uranium (VI) and nitrate
Jan 18, 2020
Nuclear wastes contain high nitrate concentration along with radionuclides like U (VI). Also, several reports suggest the presence of U (VI) and nitrate as co-contaminants in groundwater. The denitrifying bacteria consortia at MFC cathode produced phosphatase enzyme, which catalyzed the controlled release of phosphate from glycerol 3 phosphate. The inorganic phosphate combined with U (VI) resulting in insoluble uranyl phosphate. Ninety percent of initial U (VI) added in the biocathode could be recovered as Uranyl phosphate. XRD analysis confirmed the presence of uranyl phosphate precipitating at the cathode. Nitrate acted as an electron acceptor at the cathode, enabling completion of the MFC circuit and simultaneous nitrate and U (VI) removal. Since the process was performed in the MFC; the remediation was accompanied by power output. The power density of 2.91 Wm-3 and nitrate removal rate of 0.130 kg NO3--N m-3 d-1 was achieved. The 16S rDNA based community analysis revealed a high abundance of Pseudomonas species in biocathode. This study demonstrates the applicability of MFC for simultaneous nitrate and U (VI) removal while producing electrical energy.
Jan 1, 2018
In this study, a promising microbial fuel cell (MFC) system has been developed, wherein algae is cultivated in the cathode chamber, algae biomass is harvested and lipids are extracted. The lipid extracted algal (LEA) biomass was then used as an electron donor substrate. The performance of MFCs fed with LEA biomass was compared with that of fruit waste fed MFCs (FP-MFCs), wherein LEA-fed MFC was superior in all aspects. Power density of 2.7 W m−3 was obtained by LEA-fed MFCs which is 145% and 260% higher than FP MFC and control MFC respectively. The volumetric algae productivity of 0.028 kg m−3 day−1 in cathode chamber was achieved. The system was able to generate 0.0136 kWh Kg−1 COD day−1 of electric energy and 0.0782 kWh m−3 day−1 of algal oil energy. The proposed system is a net energy producer which does not rely heavily on the external supply of electron donor substrates.
Halophilic starch degrading bacteria isolated from Sambhar Lake, India, as potential anode catalyst in microbial fuel cell: A promising process for saline water treatment
May 1, 2018
In this study, Microbial Fuel Cell (MFC) capable of treating saline starch water was developed. Sodium chloride (NaCl) concentrations ranging from 500 mM to 3000 mM were tested at the anode. Nitrate was used as an electron acceptor at the biocathode. The halophilic bacteria were isolated from Sambhar Lake, India. Results indicated successful removal of starch (1.83 kg/m3-d) and nitrate (0.13 kg/m3-d NO3−-N) with concomitant power output of 207.05 mW/m2 at 1000 mM NaCl concentration. An increase in power density from 71.06 mW/m2 to 207.05 mW/m2 (2.92 folds) was observed when NaCl concentration was increased from 500 mM to 1000 mM. A decline in power density was observed when the salt concentrations >1000 mM were used. Concentration of 3000 mM supported power output as well as the highest starch degradation (3.2 kg/m3-d) and amylase activity of 2.26 IU/ml.
Isolation, identification and characterization of Cystobasidium oligophagum JRC1: A cellulase and lipase producing oleaginous yeast.
Microbial fuel cell assisted nitrate nitrogen removal using cow manure and soil
2017
Oleaginous yeast closely related to Cystobasidium oligophagum was isolated from soil rich in cellulosic waste. The yeast was isolated based on its ability to accumulate intracellular lipid, grow on carboxymethylcellulose (CMC) and produce lipase. It could accumulate up to 39.44% lipid in a glucose medium (12.45 ± 0.97 g/l biomass production). It was able to grow and accumulate lipids (36.46%) in the medium containing CMC as the sole carbon source. The specific enzyme activities obtained for endoglucanase, exoglucanase, and β-glucosidase were 2.27, 1.26, and 0.98 IU/mg respectively. The specific enzyme activities obtained for intracellular and extracellular lipase were 2.16 and 2.88 IU/mg respectively. It could grow and accumulate lipids in substrates including glycerol (42.04%), starch (41.54%), xylose (36.24%), maltose (26.31%), fructose (24.29%), lactose (21.91%) and sucrose (21.72%). The lipid profile of the organism was suitable for obtaining biodiesel with desirable fuel properties.
Jan 12, 2016
Microbial fuel cells (MFCs) are emerging wastewater treatment systems with a proven potential for denitrification. In this study, we have developed a high-rate denitrifying MFC. The anode consisted of cow manure and fruit waste and the cathode consisted of cow manure and soil. The initial chemical oxygen demand (COD)/nitrate nitrogen (NO3 −-N) was varied from 2 to 40 at the cathode while keeping the anode ratio fixed at 100. NO3 −-N removal rate of 7.1 ± 0.9 kg NO3 −-N/m3 net cathodic compartment (NCC)/day was achieved at cathode COD/NO3 −-N ratio 7.31 with the current density of 190 ± 9.1 mA/m2 and power density of 31.92 ± 4 mW/m2 of electrode surface area. We achieved an open-circuit voltage (OCV) of 410 ± 20 mV at initial cathodic NO3 −-N of 0.345 g/l. The cathode COD/NO3 −-N ratio had a significant influence on MFC’s OCV and nitrate removal rate. Lower OCV (<150 mV) and NO3 −-N removal rates were observed at COD/NO3 −-N ratio >12 and <7. Experiments done at different cathode pH values indicated that the optimum pH for denitrification was 7. Under optimized biochemical conditions, nitrate removal rate of 6.5 kg NO3 −-N/m3 net cathodic compartment (NCC)/day and power density of 210 mW/m2 were achieved in a low resistance MFC. The present study thus demonstrates the utility of MFCs for the treatment of high nitrate wastes.
Effect of cathodic culture on wastewater treatment and power generation in a photosynthetic sediment microbial fuel cell (SMFC): Canna indicav/s Chlorella vulgaris
The aim of this work was to compare the performance of the two types of photosynthetic microbial fuel cells (MFCs) fed with real wastewater- one having plant Canna indica (PMFC) and the other having alga Chlorella vulgaris (AMFC) at the cathode. The chemical oxygen demand (COD), phosphate, and nitrate removal stood at 57.16% 88.81%, 59.82% for PMFC and 65.27%, 95.59%, 66.61% for the AMFC. While AMFC was slightly superior in water treatment, the power output was 6 times higher in PMFC (22.76 mW m−2) than the AMFC (3.64 mW m−2). The biomass growth was good in both systems, with biomass productivity of 0.031 Kg m−3 day−1in AMFC and a leaf area index of 0.006 in PMFC. The study's findings suggest that PMFCs are equally good or even better than AMFCs when the goal is simultaneous water treatment and power generation.
July, 2021
Performance of photo-microbial fuel cell with Dunaliella salina at the saline cathode
August, 2022