Firdausi Razali

Optimization of fresh palm oil mill effluent biodegradation with Aspergillus niger and Trichoderma virens

Abstract In this work, response surface optimization strategy was employed to enhance the biodegradation process of fresh palm oil mill effluent (POME) by Aspergillus niger and Trichoderma virens. A central composite design (CCD) combined with response surface methodology (RSM) were employed to study the effects of three independent variables: inoculum size (%), agitation rate (rpm) and temperature (°C) on the biodegradation processes and production of biosolids enriched with fungal biomass protein. The results achieved using A. niger were compared to those obtained using T. virens. The optimal conditions for the biodegradation processes in terms of total suspended solids (TSS), turbidity, chemical oxygen demand (COD), specific resistance to filtration (SRF) and production of biosolids enriched with fungal biomass protein in fresh POME treated with A. niger and T. virens have been predicted by multiple response optimization and verified experimentally at 19% (v/v) inoculum size, 100 rpm, 30.2°C and 5% (v/v) inoculum size, 100 rpm, 33.3°C respectively. As disclosed by ANOVA and response surface plots, the effects of inoculum size and agitation rate on fresh POME treatment process by both fungal strains were significant.

Production of Extracellular 5-Aminolevulinic Acid by Rhodopseudomonas Palustris in Solid-State Fermentation

Nowadays, 5-aminolevulinic acid (ALA) is widely used as non-toxic herbicide, as insecticide, and also as plant growth enhancer in agricultural application. However, their use is limited by high production cost via the route of chemical synthesis. Agricultural waste, which serves as inexpensive solid support medium, can be used to produce ALA through solid-state fermentation (SSF). In this study, production of ALA using empty fruit bunch (EFB) as solid support medium inoculated with Rhodopseudomonas palustris (R. palustris) NRRL-B4276 was conducted through SSF. Several environmental factors for the SSF process including the initial pH (2, 3, 4, 5, and 6), initial moisture content (40, 50, 60, 70, and 80 %) of the solid support medium, and incubation period (1–5 days) were investigated to study their effects for the production of ALA in SSF. The maximal yield of ALA was achieved at 38.22 ± 0.15 mg/kg substrate at the total viable cell count of 35 ± 3 × 106 CFU/g in SSF using EFB as the solid support medium inoculated with R. palustris. The optimized operating parameters including the initial pH, initial moisture content of the solid support medium, and incubation period were found to be pH 3, 60 %, and 3 days (72 h), respectively, in the presence of 40 % (v/w) inoculum at 37 °C aerobically with light under static condition.

Assessment of compost stability using single and mixed culture in a static semi-closed fed-batch reactor

Different microbial inoculums are expected to affect the degradation and stability of different compost materials. The results tend to vary more significantly in an open system due to the varied ambient conditions (temperature, moisture and air-borne microbial). To minimise such variation and avoid low reproducibility of the data, the present work was performed in a static semi-closed fed-batch reactor (SSCFBR) for better control of the composting process. The thermophilic Bacillus coagulans (BC) and the commercial effective microorganisms (EM) were used as the microbial inoculum (MI) in the SSCFBR. Distilled water was used in place of the MI for the control experiments. The mixture of chicken dung (CD), wooden husk (WH), and rice husk (RH) were used as the compost materials. The MI was inoculated into the compost bed in the SSCFBR (15 L working volume) at the same initial optical density (OD) of 0.8 and the initial volume of 800 mL with a forced aeration of 0.4 L/min. The parameters for the assessment of compost stability included the temperature, moisture content, oxygen uptake rate (OUR) and carbon dioxide emission rate (CER). BC showed comparable or better results to that achieved by the commercial EM. The temperature profile for both composts showed similar patterns where the highest peak of temperature was recorded within 1 d of composting (slightly higher for BC, 55 ± 0.8 °C and 47 ± 0.8 °C for EM). Such thermophilic temperature profile has not been observed in the control. The initial moisture content was set similar for all composts (44.5 ± 0.7 %). The moisture content declined slightly different for both MI compost (to 39.0 ± 0.6 % for BC and 36.6 ± 1.2 % for EM). Both composts showed very similar trend in the OUR. A higher evolution rate of carbon dioxide (CO2) was observed for the compost with BC for the first three days (0.06 ± 0.014 g/mol) as compared to that by EM (0.02 ± 0.007 g/mol). On the 4th d of composting, the production of CO2 in EM compost showed a near constant value (0.008 ± 0.002 g/mol) but the BC compost showed the rate of 0.06 ± 0.01 g/mol the 5th d and declined to 0.02 ± 0.004 g/mol on the 7th d. For both composting cases, the highest rate of CO2 was observed at the highest peak of temperature. The SSCFBR has been designed and could be used to facilitate the assessment of compost stability in a closed system with improved reproducibility of the data for composting.

Public funded heritage rejuvenation mechanism in Georgetown, Penang

On July 7, 2008, Georgetown was formally inscribed as a UNESCO World Heritage Site. It was recognized for its unique heritage of a living multicultural community. Since then there have been various conservation projects within the vicinity of Georgetown, but the initiative seems to be fighting a losing battle. There have been a few major significant conservation projects developed especially in the cultural enclave in order to maintain the status-quo of a world heritage site. Engaging Love Lane as a pilot project to experiment on a new mechanism of heritage rejuvenation involving public participation and extensive use of technological infrastructure could be an alternative approach in conservation development. Heritage value in Love Lane will be enhanced with the use of information technology via the ‘Groupon’ method which has been proven successful among online shoppers. It is about time this method of collective fund is put to the test in conservation and management of heritage sites. This theoretical urban design exercise covers a 12-acre block of old shophouses in restoring appropriate historical artifacts through smart partnership among stakeholders. If the project is a success, it could be the key to safeguarding not only Penang, but hundreds of world heritage sites facing similar problems.

Mediating fragile ecologies through digital technologies for sustainable tourism

Natural environments such as the rainforest, mangrove and marine ecologies are part of Malaysia’s natural resources. Other than being useful for their physical contents, the contexts too are highly valuable. These ecologies are priceless in the tourism industry. However, mass tourism affects these fragile ecologies in negative ways. Unchecked tourists’ behaviors are known to destroy marine life such as the corals. Whilst totally stopping visitors into the fragile environments might not be practicable in the nearest future, there has to be an alternative mechanism whereby foreign intrusions into the sensitive ecologies could be toned down. This paper highlights an architectural experiment where digital technologies are utilised to mediate the highly sensitive natural environments. First, architectural design schemes are proposed within the context of the rainforest, mangrove and marine ecologies. Next the experiment looks at the tourists’ receptivity towards experiencing the proposed designs within the fragile ecologies via 3D digital simulation. The results from this experiment will provide the insights into using this approach as an alternative mechanism for designing towards sustainable tourism.