24 research outputs found
Fermentative Hydrogen Production from Indigenous Mesophilic Strain Bacillus Anthracis PUNAJAN 1 Newly Isolated from Palm Oil Mill Effluent
In the present study, a new mesophilic bacterial strain, identified as Bacillus anthracis strain PUNAJAN 1 was isolated from palm oil mill effluent (POME) sludge, and tested for its hydrogen production ability. Effect of physico-chemical factors such as temperature, initial pH, nitrogen source and carbon sources were investigated in order to determine the optimal conditions for hydrogen production. The maximum hydrogen yield of 2.42 mol H2/mol mannose was obtained at 35 °C and initial pH of 6.5. Yeast and mannose were used as the main carbon and nitrogen sources respectively in the course of the hydrogen production. Apart from synthetic substrate, specific hydrogen production potentials of the strain using POME was calculated and found to be 236 ml H2/g chemical oxygen demand (COD). The findings of this study demonstrate that the indigenous strain PUNAJAN 1 could be a potential candidate for hydrogen using POME as substrate
Process Enhancement of Hydrogen And Methane Production from Palm Oil Mill Effluent Using Two-Stage Thermophilic and Mesophilic Fermentation
The present study investigates the technical possibilities of hydrogen and methane production from palm oil mill effluent (POME). The production was carried out in two stage (thermophilic and mesophilic) continuous phase with recirculation of the digestate sludge. The reactors used for the present study, up-flow anaerobic sludge blanket reactor (UASB) and continuous stirred tank reactor (CSTR) were operated under thermophilic and mesophilic conditions, respectively. The UASB reactor was operated at 2 days hydraulic retention time (HRT) and 75 kgCOD m3 d−1 organic loading rate (OLR) for hydrogen production. The effluents from UASB reactor containing mainly with acetate and butyrate were directly fed into CSTR for methane production and 5 days HRT was maintained. Both UASB and CSTR reactors were operated for 120 days continuously, and a stable production of the hydrogen and methane was obtained in the separate reactors. The maximum hydrogen and methane production rate achieved was 1.92 L H2 L−d−1 and 3.2 L CH4 L−1 d−1, respectively. The cumulative hydrogen and methane yields were 215 L H2/kgCOD−1 and 320 L CH4/kgCOD−1, respectively with the total COD removal efficiency of 94%. Thermoanaerobacterium species was dominant in hydrogen reactor, while methane reactor was dominated with Methanobrevibacter sp
Effect of Organic Loading Rate on Hydrogen (H2) and Methane (CH4) Production in Two-stage Fermentation under Thermophilic Conditions using Palm Oil Mill Effluent (POME)
The present study dealt with hydrogen and methane production in a sequential up-flow anaerobic sludge blanket (UASB) and continuous stirred tank reactor (CSTR) at thermophilic temperature. The POME was used as a suitable substrate of carbon source. The effect of various OLR was investigated from 25 kg-COD/m3·d to 125 kg-COD/m3·d at a constant hydraulic retention time (HRT) of 6 h. The UASB-H2 reactor was operated successfully at the OLR of 75 kg-COD/m3·d when the proportion of H2 in biogas, volumetric production rate of H2, specific hydrogen production rate (SHPR) and H2 yield reached the maximum values of 35%, 2.1 l/d, 175.15 ml H2/g MLVSS-d and 49.22 ml H2/g CODapplied respectively. Further, the effluent from the UASB was directly fed into the CSTR at various OLR ranging from 4 kg-COD/m3·d to 20 kg-COD/m3·d for CH4 production. The maximum CH4 content, volumetric production rate of CH4, specific methane production rate (SMPR) and CH4 yield obtained were 65%, 13 l/d, 325.13 ml CH4/g MLVSS-d, and 155.87 ml CH4/g CODapplied respectively. The effluent from CH4 reactor was recycled at feed flow rate recycle ratio of 1:1 to UASB unit and pH was maintained at 5.5, subsequently resulted in COD removal of 85%
Comparison of Process Stability in Methane Generation from Palm Oil Mill Effluent using Dairy Manure as Inoculum
The potential of methane production in a continuously stirred tank reactor (CSTR) was investigated using dairy manure as inoculum at pH 6.8 and 37 °C temperature in this study. Two identical anaerobic bioreactors namely CSTR1 and CSTR2 filled with palm oil mill effluent (POME) as a carbon source were used. CSTR1 was not added with the inoculum, while CSTR2 was added with dairy manure as inoculum. Both the reactors were allowed to run for 5 days (d) in batch condition at hydraulic retention time (HRT) 10 d. The CSTR2produced 0.85 L/d gas yield and 59% methane content compared to 0.39 L/d gas yield and 20% produced in CSTR1, respectively. A better chemical oxygen demand (COD) reduction percentage of 48% was found in CSTR2 compared to CSTR1 with 33%. The investigation showed that dairy manure as inoculum has a marked influence on the start-up period and the biogas production rate
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Comparison of process stability in methane generation from palm oil mill effluent using dairy manure as inoculum
The potential of methane production in a continuously stirred tank reactor (CSTR) was investigated using dairy manure as inoculum at pH 6.8 and 37 degrees C temperature in this study. Two identical anaerobic bioreactors namely CSTR1 and CSTR2 filled with palm oil mill effluent (POME) as a carbon source were used. CSTR1 was not added with the inoculum, while CSTR2 was added with dairy manure as inoculum. Both the reactors were allowed to run for 5 days (d) in batch condition at hydraulic retention time (HRT) 10 d. The CSTR(2)produced 0.85 L/d gas yield and 59% methane content compared to 0.39 L/d gas yield and 20% produced in CSTR1, respectively. A better chemical oxygen demand (COD) reduction percentage of 48% was found in CSTR2 compared to CSTR1 with 33%. The investigation showed that dairy manure as inoculum has a marked influence on the start-up period and the biogas production rate. (C) 2017 Elsevier B.V. All rights reserved
Bioelectrofuel synthesis by nanoenzymes : novel alternatives to conventional enzymes
Recent bioinspired efforts of designing novel nanoenzyme-based electrocatalysts are driven by the urgency of making bioelectrofuels more affordable and efficient. Unlike natural enzymes, nanoenzyme-modified electrodes with large surface areas enclose numerous biomimicking active sites to facilitate enhanced microbial growth followed by increased reactant-to-bioelectrofuel conversion
Enhanced Hydrogen Production from Palm Oil Mill Effluent using Two Stage Sequential Dark and Photo Fermentation
The aim of this study was to investigate the maximum hydrogen yield as well as the chemical oxygen demand (COD) reduction from palm oil mill effluent (POME) by using two
stage sequential dark and photo fermentation. The first stage operation was carried out using Clostridium butyricum LS2, which has the maximum hydrogen yield of 0.784 ml H2/ml
POME and COD removal of 57%. The dark fermentative effluent was diluted with 50% of tap water (DEPOME-50), for better penetration of light and was subsequently used as substrate
to the second stage fermentation using Rhodopseudomonas palustris as hydrogen producer. Hydrogen production was monitored under optimized light illumination of 7 klux, in batch mode. The two-stage fermentation enhanced the total hydrogen yield from 0.784 (dark fermentation) to 3.064 ml H2/ml POME (dark/photo-fermentation). Meanwhile, a 93% of
total COD removal was also achieved
Impacts of Nano-Metal Oxides on Hydrogen Production in Anaerobic Digestion of Palm Oil Mill Effluent - A Novel Approach
In the present study, hydrogen production from palm oil mill effluent (POME) was investigated with the incorporation of nanoparticles (NPs) comprising of nickel (NiO) and cobalt oxides (CoO). The NPs of NiO and CoO were prepared using hydrothermal method and were further applied to analyse, their effect on hydrogen production. The results demonstrated that, a maxima volumetric hydrogen production rate of 21 ml H2/L-POME/h with the hydrogen yield of 0.563 L H2/g-CODremoved was obtained with 1.5 mg/L concentration of NiO NPs. On the other hand, the addition of CoO NPs produced maximum volumetric hydrogen production rate of 18 ml H2/L-POME/h with a hydrogen yield of 0.487 L H2/g-CODremoved with 1.0 mg/L of CoO NPs. Results showed that addition of optimal concentration of NiO and CoO NPs to the POME enhances the hydrogen yield by 1.51 and 1.67 fold respectively. Besides, this addition of NiO and CoO enhanced the COD removal efficiency by 15 and 10% respectively as compared to an un-additive NPs POME. The toxicity of NPs was also tested using bacterial viability test, which revealed that application of 3.0 mg/L of NiO and CoO NPs to modified Luria-Bertani (LB) medium had 63% and 83% reduction in bacterial cell growth. The results concluded that supplementation of NiO and CoO NPs under an optimal range to the wastewater can improve the hydrogen productivity
Lead Induced Oxidative Stress and Alteration in the Activities of Antioxidative Enzymes in Rice Shoots
Physiological responses of Oryza sativa L. to lead excess (10 and 50 μM) were studied in hydroponic system after
48- and 96-h exposure. The Pb accumulation in stressed rice shoots was concomitant with increased metal concentration
in the growth media and duration of exposure. Pb stress resulted in enhanced lipid peroxidation accompanied by altered activities of antioxidants. A substantial increase in α-tocopherol content of the Pb stressed rice shoots was observed suggesting its important role as an antioxidant. Among the antioxidant enzymes studied, the activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX) increased in Pb-treated rice shoots, while that of catalase (CAT) was declined. Activity of an important ascorbate-glutathione cycle enzyme glutathione reductase (GR) also increased significantly in Pb-treated shoots. Results suggest that Pb toxicity results in induction of oxidative stress in rice shoots and α-tocopherol accumulation and upregulation of SOD, APX, and GR activities play an effective role in acclimatization to Pb stress
Evaluation of Antilipolytic, Antioxidant and Antibacterial Activities of Selected Ferns
In the present study, three ferns were used (Adiantum capillus-veneris Cheilanthes albomarginata and Asplenium pumilum,) to identify their functional compounds to reduce obesity. The methanolic fern-extract (MFE) of these ferns was assessed for anti-bacterial activity by measuring inhibition zones against a panel of pathogenic bacterial strains using the agar diffusion method. MFE at a concentration of 25 μg /ml showed marked anti-bacterial activity against all bacterial strains (6mm to 23mm) zone of inhibition and was greatest against Enterobacter sp (23 mm). Out of these, the MFE of the A. veneris fern extract had the best MIC values of 2.25 μg /ml against S. aureus and Enterobacter sp. respectively. It had an inhibitory concentration (69.9 %) for 2, 2-diphenylpicryl-1-picryl-hydrazyl (DPPH) scavenging activity. The MFE of the A. veriens also possessed good anti-lipolytic activity (76.5%) against a porcine pancreatic lipase (PPL) and cholesterol oxidase inhibition (89%). The hemolytic activity of A. veneris was found to be 27.6% at 6.25 µg/mL of MFE. This result showed that the MFE of A. veriens is not only a potent source of natural anti-oxidants and anti-bacterial activities but also possesses efficient cholesterol degradation and anti-lipolytic activities, which would be beneficial in body weight management