Phang Lai Yee

Utilization of oil palm decanter cake for cellulase and polyoses production

The abundance of oil palm decanter cake (OPDC) is a problem in oil palm mills. However, this lignocellulosic biomass can be utilized for cellulase and polyoses production. The effectiveness of chemical and physical pretreatment in reducing the lignin content was studied by saccharification using a Celluclast 1.5 L and scanning electron microscope. Physicochemical pretreatment of OPDC with 1% (w/v) NaOH and autoclaving at 121°C for 20 min increased potential polyoses produced to 52.5% and removed 28.7% of the lignin content. The optimized conditions for cellulase production by a locally isolated fungus were a time of 120 h, a substrate of untreated OPDC, a spore concentration of 1 × 107 spore/mL, a temperature of 30°C, and a pH between 7.0 and 7.5. Trichoderma asperellum UPM1 produced carboxymethylcellulase (CMCase), β-glucosidase and filter paper activity (FPase) in the following concentrations: 17.35, 0.53, and 0.28 U/mL, respectively. Aspergillus fumigatus UPM2 produced the CMCase, β-glucosidase and FPase in the following amounts: 10.93, 0.76, and 0.24 U/mL. The cellulases from T. asperellum UPM1 produced 2.33 g/L of polyoses and the cellulases from A. fumigatus UPM2 produced 4.37 g/L of polyoses.

Harnessing the potential of ligninolytic enzymes for lignocellulosic biomass pretreatment

Abundant lignocellulosic biomass from various industries provides a great potential feedstock for the production of value-added products such as biofuel, animal feed, and paper pulping. However, low yield of sugar obtained from lignocellulosic hydrolysate is usually due to the presence of lignin that acts as a protective barrier for cellulose and thus restricts the accessibility of the enzyme to work on the cellulosic component. This review focuses on the significance of biological pretreatment specifically using ligninolytic enzymes as an alternative method apart from the conventional physical and chemical pretreatment. Different modes of biological pretreatment are discussed in this paper which is based on (i) fungal pretreatment where fungi mycelia colonise and directly attack the substrate by releasing ligninolytic enzymes and (ii) enzymatic pretreatment using ligninolytic enzymes to counter the drawbacks of fungal pretreatment. This review also discusses the important factors of biological pretreatment using ligninolytic enzymes such as nature of the lignocellulosic biomass, pH, temperature, presence of mediator, oxygen, and surfactant during the biodelignification process.

Separation and recovery of organic acids from fermented kitchen waste by an integrated process.

Organic acids produced from anaerobic digestion of kitchen waste were recovered using a new integrated method which consisted of freezing and thawing, centrifugation, filtration and evaporation. The main organic acid produced was lactic acid (98%). After the freezing and thawing process, 73% of the total suspended solids were removed and the organic acids were elevated from 59.0 to 70 g/L. The evaporation technique was used to further concentrate the organic acids up to 224 g/L. Using the integrated recovery method, the reduction of the total suspended solids in the solution achieved was about 93%. The material balance for the recovery process was also presented.

Genetic characterization of Porcine Circovirus 2 found in Malaysia

BackgroundPorcine circovirus type 2 is the primary etiological agent associated with a group of complex multi-factorial diseases classified as Porcine Circovirus Associated Diseases (PCVAD). Sporadic cases reported in Malaysia in 2007 caused major economic losses to the 2.2 billion Malaysian ringgit (MYR) (approximately 0.7 billion US dollar) swine industry. The objective of the present study was to determine the association between the presence of PCV2 and occurrences of PCVAD.ResultsThis study showed that 37 out of 42 farms sampled were positive for PCV2 using PCR screening. Thirteen whole genome of PCV2 isolates from pigs with typical PCVAD symptoms were successfully sequenced. These isolates shared 98.3-99.2% similarities with sequences of isolates from the Netherlands. All thirteen isolates fell into the same clade as PCV2b isolates from other countries. Amino acid sequence analysis of the putative capsid protein (ORF2) of the PCV2 revealed that there are three clusters found in Malaysia, namely cluster 1C and 1A/1B. Of interest, three of the isolates (isolates Mal 005, Mal 006 and Mal 010) had a proline substitution for arginine or isoleucine encoded at nt. position 88-89. Eight of the isolates had mutations at the C terminus of the putative capsid protein suggestive of higher pathogenicity which may account for the high reports of PCVAD clinical symptoms in 2007.ConclusionPhylogenetic study suggests that there may be a link between movements of animals by import of breeders into the country being the route of entry of the virus. While it is not possible to eradicate the virus from commercial pigs, the swine industry in Malaysia can be safeguarded by control measures implemented throughout the country. These measures should include improved biosecurity, disease surveillance; vaccination as well as enforcement of regulations formulated to control and prevent the spread of this disease on a national scale.

Visualization of Core-Shell PHBV Granules of Wild Type Comamonas sp. EB172 In Vivo under Transmission Electron Microscope

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) granule formation in vivo in wild type Comamonas sp. EB172 grown in mixed organic acids under nitrogen limitation were visualized under transmission electron microscope (TEM). The early stages of PHBV production revealed dark-stained mediation elements near the center of the cell supporting the third model of granule formation. The native granules revealed characteristic core-shell structure in which white PHB cores were surrounded by darker PHBV shells. In vitro, the copolymer showed bimodal molecular weight distribution and exhibited two melting peaks in the differential scanning calorimeter (DSC) thermogram, supporting the formation of block copolymer.

Adsorption of vanillin using macroporous resin H103

Six resins (Amberlite XAD-16, Amberlite XAD-2, Sepabeads SP207, DIAION HP-20, DM11 and H103) were tested for vanillin adsorption in aqueous solution. All of the resins gave more than 95% adsorption rate except for Amberlite XAD-2 and DM11. Resin H103 was selected for the subsequent work due to its high adsorption capacity and low cost. A kinetic analysis revealed that the adsorption process followed pseudo-second-order kinetic model and occurred rapidly. The equilibrium point was reached after 90 minutes of reaction. Adsorption isotherm was also determined at 25 °C and it was fitted to Langmuir and Freundlich equations using linear regression and non-linear regression (sum of squares) methods. The regression shows that the adsorption of vanillin onto resin H103 followed Langmuir model (R2 = 0.9984) with a maximum capacity of 73.015 mg/g.

Nitrification of high-strength ammonium landfill leachate with microbial community analysis using fluorescence in situ hybridization (FISH)

Nitrification of mature sanitary landfill leachate with high-strength of N-NH4 + (1080—2350 mg L-1) was performed in a 10 L continuous nitrification activated sludge reactor. The nitrification system was acclimatized with synthetic leachate during feed batch operation to avoid substrate inhibition before being fed with actual mature leachate. Successful nitrification was achieved with an approximately complete ammonium removal (99%) and 96% of N-NH4 + conversion to N-NO- 3 . The maximum volumetric and specific nitrification rates obtained were 2.56 kg N-NH4 + m-3 day-1 and 0.23 g N-NH4 + g-1 volatile suspended solid (VSS) day-1, respectively, at hydraulic retention time (HRT) of 12.7 h and solid retention time of 50 days. Incomplete nitrification was encountered when operating at a higher nitrogen loading rate of 3.14 kg N-NH4 + m-3 day-1. The substrate overloading and nitrifiers competition with heterotrophs were believed to trigger the incomplete nitrification. Fluorescence in situ hybridization (FISH) results supported the syntrophic association between the ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria. FISH results also revealed the heterotrophs as the dominant and disintegration of some AOB cell aggregates into single cells which further supported the incomplete nitrification phenomenon.

Synthesis, Characterization, and Structural Properties of Intracellular Copolyester Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Produced by Comamonas sp. EB 172 from Renewable Resource

Microbial copolymer was produced by a local isolate, Comamonas sp. EB 172, using mixed organic acids such as acetic, propionic, and butyric acids as carbon sources in pH-stat fed-batch fermentation. Maximum polymer production (6.59 g/L) was achieved at 50 h of fermentation when 73.64 g/L mixed acids, generated from the acidogenic fermentation of palm oil mill wastewater, were used. Accumulation of polymer in the cell was 70% (wt/wt), which was observed under transmission electron microscope. The morphological, chemical, thermal, and mechanical properties of the solvent-extracted biopolymer were determined by various techniques (SEM, GC, 13C NMR, FT-IR, TGA, and tensile testing). The copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) consisted of 87 mol% β-hydroxybutyric acid (HB) and 13 mol% β-hydroxyvaleric acid (HV). With chemical properties similar to commercial PHBV and mechanical strength of around 30 MPa and 8% elongation at break, the biopolymer offers potential for industrial applications.

Ebola and compliance with infection prevention measures in Nigeria

An outbreak of Ebola virus in Nigeria that began in July, 2014, after a Liberian man imported the virus to the country have raised the level of compliance to infection prevention and control measures in the nation. As researchers advocating for efficient infection control in both rural and urban health-care facilities and use of safe, environmentalfriendly methods to prevent infectious diseases in Nigeria, we read with interest a recent Editorial in The Lancet. The editorial emphasised the reasons why many people fear Ebola virus, and discussed the fact that if better infection control measures are in place—such as are available in medium-income or high-income countries—the long incubation period of 2–21 days of Ebola is suffi cient to treat those that become ill. Nigerians have never take infection prevention and control measures or environmental sanitation very seriously, despite the efforts of the government and advocates. However, amazingly with the Ebola outbreak, we have seen relatively improved compliance to WHO infection control practice guidelines of “clean care is safer care” (for which compliance was initially <5%) within a few weeks, because of fears about Ebola‘s mode of killing and the absence of a vaccine or cure for the disease. The fact that Ebola infection kills doctors and nurses treating victims of the disease, and the cases of the two American doctors who were infected despite their strict adherence to infection prevention and control measures, have forced many people to make a little eff ort and comply with guidelines. Raised anxieties among patients, health-care workers, and members of the community in fear of contracting the virus from each other have improved the use of handwashing techniques, not only in hospitals, but also in banks, markets, public places, and in communities, as advised by health-care workers through word of mouth, on print and social media, and in religious places. Use of ordinary soap, sanitisers, and even just ordinary water to wash hands after contact with other people has increased substantially, and more people are refusing to shake hands with strangers. Dissatisfaction with the world response to the Nigerian Ebola outbreak among many Nigerians; travel restrictions and stigmatisation of African communities abroad; an indefi nite strike initiated by medical doctors in the country at the start of the outbreak; the rate at which people are dying needlessly in neighbouring Liberia, Guinea, and Sierra Leone; and reports of doctors and nurses fl eeing when profusely bleeding accident victims are brought to hospitals have forced some Nigerians to go to extremes, such as following the advice of a mere rumour suggesting the use of concentrated salt solution for drinking and washing as a prevention or cure. Such misinformed control measures are not being used for a cholera outbreak that is occurring simultaneously in some areas of Nigeria. The outbreak, which has affected at least 352 people in two states within 3 months, has received less sympathy and fi nancial support from the community and government than Ebola, but has subsided as a result of improved infection prevention and control measures in the aff ected communities because of fears about Ebola. In a recent survey that we did in Nigeria of 56 health-care workers and 60 members of the community (23 rural and 37 urban dwellers) about measures taken by the government to curtail the spread of Ebola, many agreed that Ebola is real and that the preventative measures are acceptable, even though some religious and cultural rights need to be forfeited. Only seven of the 60 community members interviewed have never practiced handwashing and are never cautious about touching ill people even after the outbreak. They believe that Ebola does not really exist and is merely western propaganda. We have noted improvements in actions by all the stakeholders in Nigeria listed in a call to action for adoption of the Chennai declaration in combating spread of hospitalacquired infections and in strict adherence to the NICE quality standards of infection prevention and control and to WHO guidelines. Such improvements show that the outbreak of Ebola has successfully forced the Nigerian Government, non-governmental organisations, the media, and communities to take infection prevention and control issues seriously.

Performance of Short Chain Length Polyhydroxyalkanoate Production by Comamonas sp EB172 in Large Scale Bioreactors Based on Constant Impeller Tip Speed

Aims: In this study, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) or PHBV, a short chain length polyhydroxyalkanoates (PHAs) production by a local isolate Comamonas sp. EB172 using 500 g/L mixed organic acids were investigated in 10 L and 150 L stirred tank bioreactors based on constant impeller tip speed (minimum 0.56 m/s and maximum 2.22 m/s). Original Research Article Mumtaz et al.; BBJ, 13(2): 1-11, 2016; Article no.BBJ.24684 2 Results: The ratio of the three acids i.e., acetic, butyric, and propionic, were 2:1:1, mimicking clarified mixed acids obtained from anaerobically treated palm oil mill effluent. In pH controlled fedbatch cultivation, in 10 L bioreactor, the strain could accumulate 84% PHBV with biomass concentration of about 4.08 g/L under dual nutrient limitation strategy i.e., dissolved oxygen and nitrogen limited conditions. By maintaining similar tip speed in 150 L bioreactor, a final biomass concentration of 5.35 g/L with a PHBV content of 72% and volumetric productivity of 0.083 g/L/h were obtained. The calculated yield was 0.259 g PHBV/g mixed acids. Conclusion: Both the yield and PHA content in 150 L bioreactor were comparable to that obtained in 10 L scale where PHBV content ranged from 7090% (w/w) of the cell with yield of 0.270.4 g PHBV/g mixed acid, respectively. This is the first report of utilizing mixed organic acids for PHBV biosynthesis in large scale.