Biohydrogen Production from Palm Oil Mill Effluent by Locally Isolated Clostridium Butyricum Eb6

Hydrogen is a renewable, clean source of energy which has a great potential to be an alternative fuel. Abundant biomass from various industries could be a source for biohydrogen production where combination of waste treatment and energy production would be an advantage. Potential biomass that could be the substrates for biohydrogen generation include food and starch-based wastes, cellulosic materials, dairy wastes, palm oil mill effluent and glycerol. The objectives of this study were to isolate biohydrogen producing bacteria, to maximize the biohydrogen production in a synthetic medium and palm oil mill effluent (POME) and to improve the strain by overexpressing the hydrogenase gene in the host cell. A biohydrogen producer was successfully isolated from anaerobic POME sludge. The strain, designated as Clostridium butyricum EB6, efficiently produced biohydrogen during active cell growth. Controlled study was done on synthetic medium with 10 g/L glucose resulted in biohydrogen production at 948ml H2/L-medium and volumetric biohydrogen production rate of 172 mL H2/L-medium/h at initial pH 5.5. The supplementation of yeast extract at 4 g/L was found to have a significant effect with the highest biohydrogen production of 992 mL H2/L-medium. The effect of pH on biohydrogen production from POME was investigated, with the optimum biohydrogen production ability at pH 5.5. The maximum biohydrogen production and maximum volumetric biohydrogen production rate were at 3195 mL H2/L-medium and 1034 mL H2/L-medium/h, respectively. The biohydrogen content in the biogas produced was in the range of 60 - 70%. Optimization of biohydrogen production using synthetic medium was done on pH, glucose and iron concentration according to response surface methods (RSM) analysis. By central composite design (CCD) results, pH, glucose concentration and iron concentration were shown to significantly influence the biohydrogen gas production individually, interactively and quadratively (P<0.05) with some exception. The CCD results indicated that pH 5.6, 15.7 g/L glucose and 0.39 g/L FeSO4 was the optimum condition for biohydrogen production which gave a yield of biohydrogen at 2.2 mol H2/mol glucose. For the confirmation experiment model, t-test result showed that experimental data curve had a high confidence at 95% with t = 2.225. Based on the results of this study, optimization of the culture condition for C. butyricum EB6 significantly increased the biohydrogen production.Clostridium butyricum EB6 successfully produced hydrogen gas from POME. Central composite design and response surface methodology were applied to determine the optimum conditions for biohydrogen production (Pc) and maximum biohydrogen production rate (Rmax) from POME. Experimental results showed that the pH, temperature and chemical oxygen demand (COD) of POME affected both the biohydrogen production and production rate individually and interactively. The optimum conditions for biohydrogen production (Pc) was pH 5.69, temperature 36ºC and 92 g COD/L, with an estimated value of 306 mL H2/g carbohydrate. The optimum conditions for maximum biohydrogen production rate (Rmax) was pH 6.52, temperature 41ºC and 60 g COD/L, with an estimated value of 914 ml H2/ h. An overlay study was carried out to get an overall model optimization. The optimized conditions for the overall model was pH 6.05, temperature 36ºC and 94 g COD/L. [Fe]-hydrogenase (hydA) gene of C. butyricum EB6 was successfully amplified from the genomic DNA. Sequencing results of the hydA gene was identified with open reading frames of 1725 bp which encodes hydA of 574 amino acids with approximate size of 64 kDaltons. The hydA of C. butyricum was found 80.5% similar to hydA of C. acetobutylicum P262 and closely similar to Clostridia hydrogenase. A modified method of electroporation on C. butyricum EB6 was established for transformation of hydA. A hydA-expressing recombinant EB6 was successfully obtained with higher biohydrogen production from 4.2 L-H2/ L-medium to 4.8 L-H2/ L-medium compared to the wild type

Applications of Credit Scoring Models

The application of credit scoring on consumer lending is an automated, objective and consistent tool which helps lenders to provide quick loan decisions. In order to apply for a loan, applicants must provide their attributes by filling out an application form. Certain attributes are then selected as inputs to a credit scoring model which generates a credit score. The magnitude of this credit score is proved to be related to the credit quality of the loan applicant. As such, it is used to determine whether the loan will be granted, and also the amount of interest being charged. Currently, little effort has been devoted to verifying the correctness of the reported attributes provided by prospective borrowers. Moreover, with a long history of use of the same credit scoring model, borrowers will learn about the characteristics being used by the lender to make loan decisions, and may be motivated to lie about their attributes in order to increase their chances of loan approval. This thesis examines the effect on consumer lending if some borrowers strategically falsify their attributes on the application form. Under normal circumstances, analysts believe that using a larger dataset to develop credit scoring models will increase model accuracy. We will show that if some borrowers respond dishonestly to some questions on the application form, using higher dimensional data to build models will increase the associated accumulated error, and may result in having a more complex model but with low predictive power compared against using a dataset with lower dimensions. Furthermore, we will show that it is profitable for lenders to spend extra cost to directly eliminate lies in the dataset. In particular, we will examine the optimal amount of effort that lenders should spend on identifying liars in order to equilibrate between risk and return. However, we will also show that it is still possible for fraudulent loan applicants to eventually adjust their lies to escape from credit checks and get loans. Indeed the business of consumer lending may usefully be modeled as a game performed between the lender and the borrower. We will explore the cost to make a clever lie on the attributes and the cost to verify the correctness of the reported data towards the interaction between the lender and bad liars. The impact of having liars in the business not only affects the profitability of lenders, but also lowers the utility of those borrowers who always repay their loans and the utility of the economy as a whole. The proposed issues will be studied using discriminant analysis on simulated data, and then further assume the characteristics of borrowers follow half triangular distribution to present theoretical results. This research shows the importance of enriching data before making loan decisions. It can help lending financial institutions to reduce risk and maximize profit, and it also shows that it is feasible for customers to lie intelligently so as to evade credit checks and get loans

UTILITY OF PHOSPHATIDYLINOSITOL 3-KINASE INHIBITORS IN GASTROINTESTINAL CANCER

Ph.DDOCTOR OF PHILOSOPH

Primary headache in the elderly in South-East Asia

Headache aetiology and presentation are considerably different in elderly individuals. However, literature on headache characteristics among Asians is limited. The objective of this study was to evaluate the headache characteristics among elderly in an outpatient clinic setting in Malaysia, a South-East Asian country with diverse ethnicity. In this prospective cross-sectional study, patients presenting with headache to Neurology and Primary Care Clinics of University Malaya Medical Centre between February 2010 and July 2010 were included. Data for consecutive eligible adult patients were entered in a prospective headache registry. International Headache Criteria II (ICHD-II) were used to classify various headache subtypes. Patients with headache due to intracranial space occupying lesions were excluded. Patient were divided into two age groups—elderly (55 years and above) and younger (less than 55 years of age). Of the 175 screened patients, 165 were included in the study—70 in elderly age group and 95 in younger group. Tension-type headache was the commonest subtype (45.7 %) among the elderly while Migraine without aura (54.7 %) was more common in young adults. More elderly patients suffered from chronic daily headache as compared to younger patients (47.1 vs. 28.4 %; p = 0.015). Headache subtypes and frequency differ considerably among elderly South East Asian patients

Engineering of E. coli for increased production of L-lactic acid

An over-expressed L-ldh gene derivative of Escherichia coli BAD-ldh was developed. L-ldh gene from Enterococcus facelis KK1 consisted of an open reading frame of 954 bp encoding 316 amino acids. L-ldh gene was cloned into pBAD vector and transformed into E. coli SZ85 by electroporation. SDS-page and western blotting method confirmed the presence of recombinant L-LDH enzyme with the approximate size of 40 kD. The activity of L-lactate dehydrogenase was achieved at 170 U ml-1. E. coli BAD85 was found to produce 0.62 g l-1 of lactic acid from 1 g l-1of fructose in 24 h. L-ldh gene from was successfully transformed into E. coli SZ85 with the maximum production of L-lactic acid at 0.62 g l-1

Early Mathematics learning in reading and writing numerals: Learning through "What are the numbers?" A picture book made up flora and fauna in Borneo.

Learning through picture books is a method which is widely used in preschools to teach mathematics. However, the research findings on the benefits of using picture books in learning mathematics remain inconclusive. This study aimed to i) investigate the effects of a picture book entitled “What are the numbers?” (a picture book made up flora and fauna in Borneo) on early mathematics achievement (reading and writing numerals up to 20) and ii) to get feedback on how appropriate the use of “what are the numbers” from teachers and parents. The book consists elements of critical thinking, communication, collaboration and creative thinking. The effects were measured by comparing the change in early mathematical ability of children in reading and writing numerals up to 20 by using the Rasch measurement model. The mean of the pre-test achievement was -1.99 logits and the mean of the post-test achievement was 1.75 logits which shows a difference of 3.74 logits. The effect size of the difference between the post-test and pre-test achievement was 1.4, which is considered large. Teachers and parents gave positive feedback on the use of the picture book. They commented that the picture book is able to attract children’s attention, enhance their thinking skills and nurture creativity among children. In conclusion, the picture book based on the 4C approach enhanced early mathematics achievement of children

Biohydrogen production from biomass and industrial wastes by dark fermentation

Hydrogen is a clean energy carrier which has a great potential to be an alternative fuel. Abundant biomass from various industries could be a source for biohydrogen production where combination of waste treatment and energy production would be an advantage. This article summarizes the dark fermentative biohydrogen production from biomass. Types of potential biomass that could be the source for biohydrogen generation such as food and starch-based wastes, cellulosic materials, dairy wastes, palm oil mill effluent and glycerol are discussed in this article. Moreover, the microorganisms, factors affecting biohydrogen production such as undissociated acid, hydrogen partial pressure and metal ions are also discussed

Optimization of biohydrogen production by Clostridium butyricum EB6 from palm oil mill effluent using response surface methodology

Clostridium butyricum EB6 successfully produced hydrogen gas from palm oil mill effluent (POME). In this study, central composite design and response surface methodology were applied to determine the optimum conditions for hydrogen production (Pc) and maximum hydrogen production rate (Rmax) from POME. Experimental results showed that the pH, temperature and chemical oxygen demand (COD) of POME affected both the hydrogen production and production rate, both individually and interactively. The optimum conditions for hydrogen production (Pc) were pH 5.69, 36degreeC, and 92g COD/l; with an estimated Pc value of 306ml H2/g carbohydrate. The optimum conditions for maximum hydrogen production rate (Rmax) were pH 6.52, 41degreeC and 60g COD/l; with an estimated Rmax value of 914ml H2/h. An overlay study was performed to obtain an overall model optimization. The optimized conditions for the overall model were pH 6.05, 36degreeC and 94g COD/l. The hydrogen content in the biogas produced ranged from 60% to 75%

Biohydrogen production by Clostridium butyricum EB6 from palm oil mill effluent

A hydrogen producer was successfully isolated from anaerobic digested palm oil mill effluent (POME) sludge. The strain, designated as Clostridium butyricum EB6, efficiently produced hydrogen concurrently with cell growth. A controlled study was done on a synthetic medium at an initial pH value of 6.0 with 10 g/L glucose with the maximum hydrogen production at 948 mL H2/L-medium and the volumetric hydrogen production rate at 172 mL H2/L-medium/h. The supplementation of yeast extract was shown to have a significant effect with a maximum hydrogen production of 992 mL H2/L-medium at 4 g/L of yeast extract added. The effect of pH on hydrogen production from POME was investigated. Experimental results showed that the optimum hydrogen production ability occurred at pH 5.5. The maximum hydrogen production and maximum volumetric hydrogen production rate were at 3195 mL H2/L-medium and 1034 mL H2/L-medium/h, respectively. The hydrogen content in the biogas produced was in the range of 60–70%