Molecular Phylogeny and Characteristics of Methanogens from a Palm Oil Mill Anaerobic Tank

This study was set up to investigate the phylogeny of and characterize the methanogenic population in anaerobic tank for treating palm oil mill effluent. In this study, environmental DNA was extracted and purified from wastewater sludge by using a simplified and less time consuming procedure (Malaysian Patent Pending Number: PI20082842 filed on 30/07/2008) and the results obtained were compared to that of other three existing protocols i.e. Ogram et al., Tsai and Olson, and Jacobsen and Rasmussen methods which are normally used for environmental samples. The DNA isolated from the palm oil mill anaerobic tank in FELDA Serting Hilir, was used for determining the molecular phylogeny of methanogenic archaea by using culture-independent analysis of the 16S rRNA genes amplified directly from sludge. Restriction fragment length polymorphism (RFLP) analysis, denaturing gradient gel electrophoresis (DGGE) and fluorescent in situ hybridization (FISH) were also used in combination which made the present study, the first wide-scale study carried out in Malaysia. 1260-bp 16S rRNA PCR products were cloned and sequenced. Phylogenetic analysis showed the microbes were closely affiliated with known cultured methanogenic Archaea, Methanosaeta concilii. Based on RFLP (HaeIII) analysis, just a few clones (clone SamaliEB; Genebank Accession Number: EU580025) seemed to be new species or at least new strains of Methanosaeta. This was also confirmed by DGGE analysis which showed the presence of M. concilii and Methanosarcina. sp. FISH was carried out using specifically designed 16s rRNA probes to target methanogens and bacteria. The results were in line with DGGE analysis and revealed the presence of two types of methanogens including M. concilii and Methanosarcina sp. in the anaerobic tank. Quantitative FISH showed that M. concilii had a population of 1.4 x 108/ml of wastewater sludge, while Methanosarcina sp. was 2 x 105/ml of wastewater sludge. This could be the reason of failing to get it cloned as for each 1000 clones of Methanosaeta, there was just one clone of Methanosarcina and therefore, the probability of picking up a clone affiliated to Methanosarcina was approximately 0.1 %. FISH helped to elucidate the association of methanogens and bacteria together. The findings of this study helped to understand the microbial population of the anaerobic tank for treating POME in Malaysia. The results indicate that filamentous acetate-utilizing methanogens detected in the POME anaerobic tank belong to the genus Methanosaeta based on the cell-morphology, and the phenotypic and phylogenetic characteristics described above. The data obtained also suggest that Methanosaeta is the most abundant methanogen in POME anaerobic digestion and that it plays an important role in methane production from acetate and its optimum growth conditions should be considered when an attempt is made to treat POME anaerobically. In future, these findings will provide the chance to optimize the anaerobic tank conditions to increase the methane production and “carbon oxygen demand” (COD) removal

Enhancing Staff Health and Job Performance through Emotional Intelligence and Self-efficacy

AbstractThe purpose of the research was to study the relationship between Emotional Intelligence (E.I.) and Self-Efficacy (S.E.) with demographic variables in the staff of Bahman Motor Company in Tehran. This study was descriptive. The population consisted of 2,000 staff in 2011 and the sample was 120 who were randomly selected. Emotional Intelligence Inventory (Bar-Ann) was employed as a tool. Correlation, t- test and regression were used to analysis of data. Results showed that there was significant relationship between E.I. and S.E (r=0.78) positively. There were not found significant differences between operational and administrative; and trained and untrained staff in Emotional Intelligence and Self-Efficacy. Besides, Emotional Intelligence was predicted by demographic variables and Self-Efficacy and vice versa. Emotional Intelligence and Self-Efficacy have mutual relationship with each other

Different Pretreatment Methods of Lignocellulosic Biomass for Use in Biofuel Production

Lignocellulosic biomasses are carbon neutral and abundantly available renewable bioresource material available on earth. However, the main problem that hinders its frequent use is the tight bonding within its constituents that include cellulose, hemicellulose, and lignin. The selection of pretreatment process depends exclusively on the application. Various pretreatment processes are primarily developed and utilized in effective separation of these interlinked components to take maximum benefit from the constitutes of the lignocellulosic biomasses especially for the production of biofuel. The major pretreatment methods include physical, chemical, thermophysical, thermochemical, and biological approaches. Various aspects of these different pretreatment approaches are discussed in this chapter

Accelerated Start-up of a Semi-commercial Digester Tank Treating Palm Oil Mill Effluent with Sludge Seeding for Methane Production

The modern closed digesters are becoming more popular for treating palm oil mill effluent (POME) and are currently being installed nationwide in Malaysia to replace the conventional open lagoons and tanks treatment system. This paper describes an accelerated start-up of the 500 m semi-commercial anaerobic digester 3 treating POME and methane gas recovery for clean development mechanism (CDM) project. Results showed that by direct seeding through the transfer of the sludge from either top or bottom of the open digester tank, the start-up period was significantly shortened. The bottom seed sludge transfer led to interesting results including a 24 day start-up period, stable pH condition (pH 6.8-7.2), high COD removal efficiency (>90%), satisfactory VFA to Alk ratio (<0.3), satisfactory biogas production of nearly 1.8 kg/m /d) and methane 3 composition of 50 to 60%. The presence of high amount of methanogens in the seed sludge significantly reduced the need for a long acclimatization period and the digester could be fed with POME within less than a day after the seed sludge transfer process was completed. Close examination using scanning electron microscopy (SEM) and fluorescence in situ hybridization (FISH) revealed abundant amount of bacteria and methanogens, in particular Methanosaeta sp., in the seed sludge samples, which are very important for successful acidogenesis and methanogenesis processes

Energy Storage: from Chemicals to Materials and More

This Special Issue of Energies aims to contribute to the energy storage agenda through a combination of multidisciplinary and state-of-the-art scientific knowledge, to improve energy availability, security, and the performance and competitiveness of current or future renewable energy generation systemsinfo:eu-repo/semantics/publishedVersio

The Effect of Mixing on Methane Production in a Semi-commercial Closed Digester Tank Treating Palm Oil Mill Effluent

The performance of a semi-commercial closed digester tank treating palm oil mill effluent (POME) was studied at four different mixing regimes i.e natural mixing (NM), minimal horizontal mixing (MHM), minimal horizontal and vertical mixing (MHVM) and vigorous mixing (VM). The chemical oxygen demand (COD) removal efficiency recorded satisfactory result at higher than 90% when subjected to the first three mixing regimes but reduced to the lowest of 85% when VM was applied. In the NM, MHM and MHVM experiments, the maximum total volatile fatty acids (VFA) concentration in the digester was recorded below the critical level of 1000 mg L . The MHM gave -1 the highest methane productivity at 1.4 m m d in comparison to NM at 1.0 m m d and MHVM 3 -3 -1 3 -3 -1 at 1.1 m m d. This indicates minimal mixing was required to provide good contact between 3 -3 -1 substrate and microorganisms inside the digester and to release the entrapped biogas at the bottom of the digester. The VM on the other hand was discovered to inhibit the methane production process as methane was not produced at the end of the experiment and total VFA concentration was also recorded high at 3700 mg L . The high total VFA concentration in the system may have disrupted -1 the syntrophic relationship between acidogens and methanogens and inhibited the methanogenesis

The Effect of Higher Sludge Recycling Rate on Anaerobic Treatment of Palm Oil Mill Effluent in a Semi-Commercial Closed Digester for Renewable Energy

Problem statement: A 500 m3 semi-commercial closed anaerobic digester was constructed for Palm Oil Mill Effluent (POME) treatment and methane gas capture for renewable energy. During the start-up operation period, the Volatile Fatty Acids (VFA) accumulation could not be controlled and caused instability on the system.Approach: A settling tank was installed and sludge was recycled as to provide a balanced microorganisms population for the treatment of POME and methane gas production. The effect of sludge recycling rate was studied by applying Organic Loading Rates (OLR) (between 1.0 and 10.0 kgCOD m-3 day-1) at different sludge recycling rates (6, 12 and 18 m3 day-1).Results: At sludge recycling rate of 18 m3 day-1, the maximum OLR was 10.0 kgCOD m-3 day-1 with biogas and methane productivity of 1.5 and 0.9 m3 m-3 day-1, respectively. By increasing the sludge recycling rate the VFA concentration was controlled below its inhibitory limit (1000 mg L-1) and the COD removal efficiency recorded was above 95% which indicated good treatment performance for the digester. Two methanogens species (Methanosarcina sp. and Methanosaeta concilii) had been identified from sludge samples obtained from the digester and recycled stream.Conclusion: By increasing the sludge recycling rate upon higher application of OLR, the treatment process was kept stable with high COD removal efficiency. The biogas and methane productivity were initially improved but reduced once OLR and recycling rate were increased to 10.0 kg COD m3 day-1 and 18 m3 day-1 respectively

Polyhydroxyalkanoate production from anaerobically treated palm oil mill effluent by new bacterial strain Comamonas sp. EB172

A new isolate designated as strain EB172 was isolated from a digester treating palm oil mill effluent and was investigated by polyphasic taxonomic approach. The cells were rod-shaped, Gram-negative, non-pigmented, non-spore-forming and non-fermentative. Phylogenetic analysis using the 16S rRNA gene sequence showed that the strain clustered with the genus Comamonas. Its closest neighbours were the type strains Comamonas terrigena (96.8%), Comamonas koreensis (93.4%), Comamonas composti (92.9%), and Comamonas kerstersii (91.1%). The ability of the strain EB172 to produce polyhydroxyalkanoates (PHA) when supplied with organic acids made this bacterium unique among Comamonas species. The bacterial strain was clearly distinguished from all of the existing strains by phylogenetic analysis, fatty acid composition and a range of physiological and biochemical characteristics. The G+C content of the genomic DNA was 59.1 mol%. The strain showed good growth in acetic, propionic and n-butyric acids. Comamonas sp. EB172 produced 9.8 g/l of cell dry weight and accumulated 59 (wt%) of PHAs when supplemented with mixed organic acids from anaerobically treated palm oil mill effluent. It is evident from the genotypic, phenotypic data and ability to produce PHAs that strain EB172 represents a new strain in the genus Comamonas (GeneBank accession no. EU847238)