Controlling Accumulation of Fermentation Inhibitors in Biorefinery Recycle Water Using Microbial Fuel Cells

Background Microbial fuel cells (MFC) and microbial electrolysis cells are electrical devices that treat water using microorganisms and convert soluble organic matter into electricity and hydrogen, respectively. Emerging cellulosic biorefineries are expected to use large amounts of water during production of ethanol. Pretreatment of cellulosic biomass results in production of fermentation inhibitors which accumulate in process water and make the water recycle process difficult. Use of MFCs to remove the inhibitory sugar and lignin degradation products from recycle water is investigated in this study. Results Use of an MFC to reduce the levels of furfural, 5-hydroxymethylfurfural, vanillic acid, 4-hydroxybenzaldehyde and 4-hydroxyacetophenone while simultaneously producing electricity is demonstrated here. An integrated MFC design approach was used which resulted in high power densities for the MFC, reaching up to 3700 mW/m2 (356 W/m3 net anode volume) and a coulombic efficiency of 69%. The exoelectrogenic microbial consortium enriched in the anode was characterized using a 16S rRNA clone library method. A unique exoelectrogenic microbial consortium dominated by δ-Proteobacteria (50%), along with β-Proteobacteria (28%), α-Proteobacteria (14%), γ-Proteobacteria (6%) and others was identified. The consortium demonstrated broad substrate specificity, ability to handle high inhibitor concentrations (5 to 20 mM) with near complete removal, while maintaining long-term stability with respect to power production. Conclusion Use of MFCs for removing fermentation inhibitors has implications for: 1) enabling higher ethanol yields at high biomass loading in cellulosic ethanol biorefineries, 2) improved water recycle and 3) electricity production up to 25% of total biorefinery power needs

Bilateral synchronous spermatocytic seminoma: a rare case report from rural India and literature review

Spermatocytic Seminoma is an unusual germ cell tumour known to arise from testis only. It is associated with good prognosis. Testicular tumours as such are uncommon in Asia as compared to western countries. In the literature only five cases of bilateral synchronous Spermatocytic Seminoma have been reported. Fifty years male patient presented to us with bilateral scrotal swelling and evaluation revealed neoplastic aetiology of bilateral testicular enlargement. Left side radical orchidectomy was performed initially which histopathologically revealed spermatocytic seminoma. Subsequently right side radical orchidectomy was performed after intra-op frozen section confirmation of neoplastic nature. Histopathology revealed same pathology as on left side. Immunohistochemistry of specimen from both testes was again conclusive of spermatocytic seminoma. We hereby report this rare case of Bilateral Synchronous Spermatocytic Seminoma. This is the first case report from entire Asian continent except for Japan.Pan African Medical Journal 2012; 13:3

Enzymatic Upgrading of Heavy Crudes via Partial Oxidation or Conversion of PAHs

The objective of this program was to investigate new enzyme-based technologies for upgrading of heavy oils. Enzymes were selected for screening from those capable of conversion of polyaromatic hydrocarbons (PAHs) reported in the literature. Oxidative reactions of PAHs using hydrogen peroxide as an oxidant with conversion to partially oxidized products were used. The enzymes (lignin peroxidase, cytochrome c) were tested in various organic solvents and found to loose activity in pure organic solvents. A thermodynamic analysis revealed lack of effective interaction between the substrate and enzyme as the cause for low activity. The protein cytochrome c was modified to work in organic media by chemical hydrophobic group attachment. Two different modifications were made: attachment of polyethylene glycol (PEG) and alkyl groups. Alkyl groups, being small could be attached at interior locations within the core of the enzyme and possibly near the active site. Increase in the threshold solvent concentration where maximum enzyme activity occurred indicated potential of this strategy for effective enzyme-substrate interaction. Further improvements in enzyme activity called for other diverse methods due to the unavailability of sufficient chemical modification sites. Genetic techniques were therefore explored for further improvements. These experiments focused on cloning of a gene for the fungal enzyme lignin peroxidase (lip) into yeast Pichia pastoris, which would allow easy manipulation of the gene. However, differences in the fungal and yeast cellular machinery impeded significant expression of the fungal enzyme. Several strategies were explored to allow higher-level expression of the enzyme, which was required for enzyme improvement. The strategies used in this investigation are described in the report. Industrial in-kind support was available throughout the project period. review of the research results was carried out on a regular basis (bimonthly reports and annual meetings) followed by suggestions for improvement in ongoing work and direction for future work. A significant portion of the industrial support was in the form of technical consultation and expert advice via meetings and phone conversations

Correlations of Social Support, Religiosity, Spirituality and Life Satisfaction in Indian Geriatrics

ABSTRACT Ageing is a nerve-racking phenomenon in a developing country like India with approximately 7% elderly population. Thus, stress management is a very important aspect of caring in the old age. Various studies have shown that practice of spirituality and religiosity as well as supportive social resources reduces stress. In India, most persons are brought up with divine ideology and religious practices. With this background, we thought, it would be interesting to study the effect of spirituality and religiosity on Life Satisfaction (L.S.) 120 subjects of either sex, above 60 years from middle class families were included in the present study. A standardized questionnaire was prepared and translated into the vernacular language; Marathi. Field work was done by trained interviewers and collected data were analyzed using SPSS. Initially internal consistency of spiritual scale of BMMRS (Brief Multidimensional Measurement of Religiosity and Spirituality) and RFQ (Royal Free Questionnaire) were checked. It was observed that no significant inconsistency was seen with the reported data. A moderate correlation was found between RFQ and BMMRS. There appears to be little effect of age and sex on L.S. Using multiple regression analyses with L.S. and well-being as separate dependent variables, the predictive value of different domains was evaluated. Besides, the influence of social support resources on L.S. was also analyzed. This study underscores that the religious values, daily spiritual experiences and social support resources were found to positively intervene with life satisfaction of elderly

Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode–rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) were located on the root surfaces, but they were more abundant colonising the graphite granular electrode. Anaerobic cellulolytic bacteria dominated the area where most of the EAB were found, indicating that the current was probably generated via the hydrolysis of cellulose. Due to the presence of oxygen and nitrate, short-chain fatty acid-utilising denitrifiers were the major competitors for the electron donor. Acetate-utilising methanogens played a minor role in the competition for electron donor, probably due to the availability of graphite granules as electron acceptors

Ceramic Microbial Fuel Cells Stack: Power generation in standard and supercapacitive mode

© 2018 The Author(s). In this work, a microbial fuel cell (MFC) stack containing 28 ceramic MFCs was tested in both standard and supercapacitive modes. The MFCs consisted of carbon veil anodes wrapped around the ceramic separator and air-breathing cathodes based on activated carbon catalyst pressed on a stainless steel mesh. The anodes and cathodes were connected in parallel. The electrolytes utilized had different solution conductivities ranging from 2.0 mScm-1 to 40.1 mScm-1, simulating diverse wastewaters. Polarization curves of MFCs showed a general enhancement in performance with the increase of the electrolyte solution conductivity. The maximum stationary power density was 3.2 mW (3.2 Wm-3) at 2.0 mScm-1 that increased to 10.6 mW (10.6 Wm-3) at the highest solution conductivity (40.1 mScm-1). For the first time, MFCs stack with 1 L operating volume was also tested in supercapacitive mode, where full galvanostatic discharges are presented. Also in the latter case, performance once again improved with the increase in solution conductivity. Particularly, the increase in solution conductivity decreased dramatically the ohmic resistance and therefore the time for complete discharge was elongated, with a resultant increase in power. Maximum power achieved varied between 7.6 mW (7.6 Wm-3) at 2.0 mScm-1 and 27.4 mW (27.4 Wm-3) at 40.1 mScm-1

Bioprocessing of crude oils and desulfurization using electro-spray reactors

Biological removal of organic sulfur from petroleum feedstocks offers an attractive alternative to conventional thermochemical treatment due to the mild operating conditions afforded by the biocatalyst. Electro-spray bioreactors were investigated for use in desulfurization due to their reported operational cost savings relative to mechanically agitated reactors and their capability of forming emulsions < 5 {micro}m. Here, the rates dibenzothiophene (DBT) oxidation to 2-hydroxybiphenyl (2-HBP) in hexadecane, by Rhodococcus sp. IGTS8 are compared in the two reactor systems. Desulfurization rates ranged from 1.0 and 5.0 mg 2-HBP/(dry g cells-h), independent of the reactor employed. The batch stirred reactor was capable of forming a very fine emulsion in the presence of the biocatalyst IGTS8, similar to that formed in the electro-spray reactors, presumably due to the fact that the biocatalyst produces its own surfactant. While electro-spray reactors did not prove to be advantageous for the IGTS8 desulfurization system, it may prove advantageous for systems which do not produce surface-active bioagents in addition to being mass transport limited

Process Considerations in the Biodesulfurization of Crude Oil

Biodesulfurization offers an attractive alternative to conventional hydrodesulfurization due to the mild operating conditions and reaction specificity afforded by the biocatalyst. The enzymatic pathway existing in Rhodococcus has been demonstrated to oxidatively desulfhrize the organic sulfbr occurring in dibenzothiophene while leaving the hydrocarbon intact. In order for biodesulfiization to realize commercial success, a variety of process considerations must be addressed including reaction rate, emulsion formation and breakage, biocatalyst recovery, and both gas and liquid mass transport. This study compares batch stirred to electro-spray bioreactors in the biodesulfurization of both model organics and actual crudes in terms of their operating costs, ability to make and break emulsions, ability to effect efficient reaction rates and enhance mass transport. Further, sulfim speciation in crude oil is assessed and compared to the sulfur specificity of currently available biocatalyst