Biohythane production from palm oil mill effluent – a preliminary evaluation of a two-stage anaerobic digestion

@#Aims:This research aims to investigate the potential of biohythane (biohydrogen and biomethane) production from palm oil mill effluent (POME) in a two-stage anaerobic digestion (AD) system.Methodology and results:A two-stage AD system was configured with a thermophilic dark fermenter (TDF) for biohydrogen (H2) production and a thermophilic anaerobic contact digester (TACD) for biomethane (CH4) production. To adjust pH 5.5 for dark fermentation, the settled sludge was recirculated from TACD to TDF. The hydraulic retention time (HRT) applied in TDF and TACD was 3.75 and 6.25 day, respectively.Conclusion, significance and impact of study:The sludge recirculation from TACD was able to adjust the pH in TDF to the optimum value of 5.5. The total COD and TSSdegradation were 63.12 and 77.94 %, respectively. The H2production in TDF was 1.54 L H2/L POME and the CH4production in TACD was 19.87 L CH4/L POME. The H2and CH4yielded 0.085 L/g CODremovedand 0.339 L/g CODremoved, respectively, with total energy recovery equivalent to 661.02 MJ/m3POME. Only 2.28 % of this energy was contributed by H2and the remaining was dominated by CH4.

Post-treatment of palm oil mill effluent (POME) using freshwater green microalgae145-

@#Aims:The effectiveness of microalgae in the post-treatment of palm oil mill effluent (POME) was being investigated for colourremoval and COD reduction. Methodology and results:Raw POME, obtained from a local palm oil mill and treated with anaerobic and aerobic processes for 50 days and 16 days of hydraulic retention time (HRT) respectively, was then used in the phycoremediation study. Three different species of microalgae (Ankistrodesmus falcatus, Scenedesmus sp. and Chlorellasp.) were inoculated in a culture media which contained 20%, 40% and 60% dilution of POME. The pH of thetreated POME sample was not adjusted and fixed at the original pH of about pH 8-9. The growth of the microalgae was determined every 2 days based on their chlorophyll concentration. Chlorellasp. showed the best adaptation and grew well in all dilutions of the treated POME sample and subsequently chosen for remediation of the POME sample without any dilution.Conclusion, significance and impact of study:Chemical oxygen demand (COD) and colour removal of POME were determined every 2 days. Chlorellasp. performed well with COD reduction and colour removal of 67.87% and 53.26%, respectively.

Screening of endophytic fungi for biofuel feedstock production using palm oil mill effluent as a carbon source

Aims: Palm oil mill effluent (POME) is a major agricultural waste product of Malaysia. The aim of this study was to identify endophytic fungi capable of producing biofuel feedstock utilizing POME. Methodology and results: Endophytes were isolated from the Nipah palm tree, Nypa fruticans, and exposed to different POME concentrations (25%, 50% and 75%), with and without the addition of nutrients. The utilization of glucose was measured using the Dinitrosalicylic Acid assay whereas the lipid content in the fungal cells was extracted using the Bligh and Dyer method with slight modifications. Three endophytic fungi that displayed the highest growth on POME were identified using ITS 1 and 4 primers and found to be related to Pestalotiopsis sp., Lasiodiplodia theobromae and Rhizoctonia bataticola. Nutrient addition caused an average increase of 8 times in biomass, indicating nitrogen requirement for cell proliferation. The highest POME concentration (75%) resulted in lower biomass yield. Furthermore, all fungal samples in high POME concentration and nutrient conditions showed a decrease in lipids accumulated per milligram of biomass whereby lipid synthesis was enhanced under nitrogen limitation (25% without nutrients). Conclusion, significance and impact of study: In conclusion, all fungal samples can be classified as oleaginous microorganisms with Pestalotipsis sp. being the most efficient (up to 70% of its biomass). This is to our knowledge the first study that shows the potential use of Pestalotiopsis sp., L. theobromae and R. bataticola for the utilisation of POME as biofuel feedstock and could in the future potentially provide an alternative approach to the treatment of POME with value-added effect.

Inoculum Sizes of Locally Isolated Phototrophic Bacterium on the Utilization of Palm Oil Mill Effluent.

Aims: To produce Rhodobacter sphaeroides strain UMSPSB3 biomass with the reduction of chemical oxygen demand (COD) from palm oil mill effluent. Study Design: Locally isolated phototrophic bacterium with different inoculum levels were used in Palm Oil Mill effluent (POME). Collected POME was characterized before used as substrate. Inoculum of bacterium was grown in synthetic media and 48 hours inoculum was used to utilize the substrate. Place and Duration of Study: Biotechnological laboratory, Borneo Marine Research Institute, University Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia, between February 2014 to April 2014. Methodology: Growth characteristics of bacterium Rhodobacter sphaeroides strain UMSPSB3 was monitored at different light intensities. Later phototrophic bacterium Rhodobacter sphaeroides strain UMSPSB3 was grown in settled non-sterilized Palm Oil Mill effluent (POME). The growth characteristics of bacterium in term of dry cell weight and total carotenoids production, and reduction of COD were compared using 10%, 20% and 30% (v/v) levels of inoculum developed in synthetic 112 media. Results: The optimum light intensity for the growth of Rhodobacter sphaeroides strain UMSPSB3 was 2.5 klux. The highest bacterial biomass (Xmax) of 6.5 g/L (dry weight) and 72% reduction of COD were obtained after 96-h culture with 20% (v/v) inoculum level. The reduction of COD (%) and cell yield (Yx/y, g cell/g COD) in POME were 82% and 0.98 respectively, after 96-h culture with 30% (v/v) inoculum. Production of carotenoids was comparatively low in bacterium using POME as substrate. Inoculum levels of 20-30% (v/v) developed in synthetic 112 media supported the growth of phototrophic bacterium in settled POME, but higher level of inoculum was required for faster removal COD from effluent. A 10% (v/v) level of inoculum in POME did not support the isolate to grow. Conclusion: Production of bacterial biomass with bioremediation of effluent could be achieved using POME as substrate with locally isolated Rhodobacter sphaeroides strain.

Biodegradation of Palm Oil Mill Effluent.

Aims: The aim of this study was to investigate the biodegradation capacity of selected indigenous fungal isolates and optimization of their degradation ability using various environmental factors such as pH, incubation temperature, nutrient concentration and inoculums size in reducing pollution effect of palm oil mill effluent (POME) in the environment. Place and Duration of Study: Two fungal isolates Candida rugosa and Geotrichum candidum used in this work were previously isolated from POME sample collected from Starline palm oil mill industries, Umukalika, Obingwa LGA, Abia state Nigeria in previous work of authors. The study was carried out from March to August, 2013. Methodology: Spore suspension was prepared by adding 10 ml of 0.1% Tween 80 onto PDA slant of 5 days old culture of Candida rugosa and Geotrichum candidum respectively. Biodegradation of POME was carried out by inoculating 0.1ml (106spores/ml) of respective fungal isolates into different 500 ml Erlenmeyer flasks containing 100ml each of raw POME. They were incubated at 30ºC on a rotary shaker (200rpm). Samples were taken every 24hrs for 144hrs to determine BOD, COD, oil & grease. Similarly, optimization of biodegradation was carried out by studying the effect of different environmental conditions such as different initial pH levels (4.0-8.0), incubation temperature (25-50ºC), concentrations of soy bean (1.5-4.5% w/v) and inoculum size (0.1-0.5 v/v). The experiments were done in triplicates. Results: Biodegradation studies with selected indigenous fungi showed that C. rugosa was able to remove (44.6%) BOD, (13.9%) COD , (50.7%) oil and grease (O&G) while G. candidum reduced BOD, COD, O&G by 46.9%,16.9% and 64,9% respectively after 144hrs. Optimization of degradation in POME using various environmental and nutrients conditions revealed that at pH 8, C. rugosa showed best degradation of COD (48.6%), BOD (74.5%), O&G (41.8%) removal while COD (59.1%), BOD (75.7%) , O&G (59.1%) removal was observed with G. candidum treatment. The optimal incubation temperature for degradation using each of fugal isolates was at 35ºC with 85.2% BOD , 71.8% COD and 67.3% O&G removal for C. rugosa , 87.3% BOD and 63.4% COD for G. candidum .The best degradation ability for C. rugosa and G. candidum were demonstrated at 3.5w/v and 2.5w/v soybean concentrations respectively. The result also showed that increase in inoculum size could not completely reduce oil and grease during degradation process possibly because no single culture supports degradation optimally due to presence of complex sugars Conclusion: The selected fungal isolates exhibited high efficiency for removal of oil and grease as well as organic matter from POME but required control of environmental conditions and nutrient expansion for the effective biodegradation of POME.

Lipase Production by Fungal Isolates Grown in Palm Oil Mill Effluent.

Aims: The present work is aimed at determining the optimum conditions of pH, temperature and nitrogen concentration for lipase production by Candida rugosa and Geotrichum candidum in POME. Place and Duration of Study: This work was carried out at the Department of Microbiology, Michael Okpara University, Umudike-Abia state, Nigeria from July to December, 2013. The organisms used in the study were isolated in a previous work by the authors. Methodology: Five milliliter of sterile water was added to respective agar slant containing the two different fungal isolates while developed growth was scrapped with sterile needle and subsequently transferred into nutrient broth contained in 250 mL Erlenmeyer flasks. These flasks were further incubated for 48 h at 28ºC on rotary shaker at 180rmp. At this stage 0.1 mL of inoculum was transferred to the production medium (POME) and incubated for 144 h. Results: At initial pH6.0, C. rugosa produce maximum lipase activity of 26.37 UmL-1 while G. candidum showed highest activity of 29.4 UmL-1 at pH 7. C. rugosa alo showed maximum lipase activity of 27.8 UmL-1 at 30ºC while G. candidum produced highest lipase activity (24.9 UmL-1) at 35ºC. The use of soybean meal in the optimization of production lipase revealed that at concentration of 3.5%w/v, the respective fungi isolates were best supported for lipase yield with maximum activity of 25.97 UmL-1 by C. rugosa and 28.32 UmL-1 by G. candidum. Conclusion: This work evaluated the effect of three culture conditions (pH, temperature and nitrogen conc.) on lipase production by G. candidum and C. rugosa cultivated in POME. Results reveal that the factors were critical to growth and lipase production by the organisms and may be useful indices in the production of lipase even from other oil processing effluents.

Use of Palm Oil Mill Effluent as Medium for Cultivation of Chlorella sorokiniana.

Aims: Palm oil mill effluent (POME) erodes the principal biophysical characteristic of both soil and water when discharged untreated but could be exploited as medium for microalgae cultivation due to its vast mineral contents. Place and Duration of study: POME samples were collected from a local palm oil processing mill at Nsukka, Enugu State, Nigeria. A part of the study was done at the Graduate School of Life and Environmental Sciences, University of Tsukuba, Japan while the rest at the University of Nigeria, Nsukka between March and September, 2012. Methodology: Chlorella sorokiniana C212 was grown in several Batches (A-D) of POME supplemented with urea (60 mg/L) before subjecting to different sterilization protocols. Cultivation was conducted in shaker flasks at 150 rpm, 1 vvm, 3000 lux and pH 7.0±0.2. Results: The filter sterilized Batch (B) promoted the highest (1070±30 mg/L) dry cell weight (DCW), lipid (156±12 mg/g-cell) and chlorophyll (1.59±0.11 mg/g-cell) contents while chemical oxygen demand (COD) decreased by 45±08%. The autoclaved medium (Batch A) gave the least DCW (310±20 mg/L), lipid production (40±05 mg/g-cell) and chlorophyll content (0.58±0.02 mg/g-cell) while COD reduced by 20±04%. The highest COD decrease (70±05%) was achieved in the unsterilized Batch (D). Batch B was most positively affected by dilution because at 75% concentration, DCW increased to 1360±30 mg/L, lipid contents to 174±10 mg/g-cell, chlorophyll to 1.87±0.14 mg/g-cell the while COD declined by 63±03%. Conclusions: POME has potential for use in microalgae cultivation with significant saving in treatment costs.

Changes in Microbial Population of Palm Oil Mill Effluent Polluted Soil Amended with Chicken Droppings and Cow Dung.

Aim of Study: To assess changes in microbial population in palm oil mill effluent (POME) polluted soil amended with chicken droppings and cow dung. Study Design: 32 plots measuring 4 m2 were mapped out in a randomized complete block design of five main plots with three replicates. Data collected were subjected to ANOVA using SPSS. Place and Duration of Study: Faculty of Agriculture, Kogi State University, Anyigba, Kogi State, Nigeria: July 2011 to November 2011. Methodology: Plots were polluted with palm oil mill effluent and subsequently remedied using varying amounts of chicken droppings and cow dung (5 kg, 10 kg and 15 kg). Microbiological analysis was carried out using Nutrient agar and Sabouraud dextrose agar for the enumeration of total aerobic heterotrophic bacteria (TAHB) and fungi (moulds and yeasts) respectively. Results: Significant difference (P=0.05) in TAHB counts after 1 month and 2 months in all treatments with the exception of unamended polluted and unpolluted control soils. The counts however, increased after 2 months in all treatments with the exception of unamended polluted soil. The overall data suggest that amendment of the POME polluted soil enhanced microbial growth, particularly after 2 months meaning that bioremediation of the polluted soil can be achieved with the organic wastes within a short time. Conclusion: Chicken droppings (at 10 kg and 15 kg/4m2 plot) and a combination of chicken droppings and cow dung (at 10 kg and 15 kg/4m2 plot) have the ability to significantly increase microbial populations in palm oil mill effluent (POME) polluted soil thereby stimulating the bioremediation of the polluted soil.

Effect of temperature and initial pH on biohydrogen production from palm oil mill effluent: long-term evaluation and microbial community analysis

Anaerobic sludge from palm oil mill effluent (POME) treatment plant was used as a source of inocula for the conversion of POME into hydrogen. Optimization of temperature and initial pH for biohydrogen production from POME was investigated by response surface methodology. Temperature of 60ºC and initial pHof 5.5 was optimized for anaerobic microflora which gave a maximum hydrogen production of 4820 ml H2/l-POME corresponding to hydrogen yield of 243 ml H2/g-sugar. Total sugar consumption and chemical oxygen demand (COD) removal efficiency were 98.7 percent and 46 percent respectively. Long-term hydrogen production in continuous reactor at HRT of 2 days, 1 day and 12 hrs were 4850 +/- 90, 4660 +/- 99 and 2590 +/- 120 ml H2/l-POME, respectively. Phylogenetic analysis of the mixed culture revealed that members involved hydrogen producers in both batch and continuous reactors were phylogenetically related to the Thermoanaerobacterium thermosaccharolyticum. Batch reactor showed more diversity of microorganisms than continuous reactor. Microbial community structure of batch reactor was comprised of T. thermosaccharolyticum, T. bryantii, Thermoanaerobacterium sp., Clostridium thermopalmarium and Clostridium NS5-4, while continuous reactor was comprised of T. thermosaccharolyticum, T. bryantii and Thermoanaerobacterium sp. POME is good substrate for biohydrogen production under thermophilic condition with Thermoanaerobacterium species play an important role in hydrogen fermentation.