Purification and characterization of cyclodextrin glucanotransferase from alkalophilic Bacillus sp. G1

A cyclodextrin glucanotransferase (CGTase) was successively purified by ammonium sulphate precipitation, and affinity chromatography on a-CD (epoxy)-Sepharose 6B column. The specific activity of the CGTase was increased approximately 2200-fold, from 8.43 U/mg protein to 18,866 U/mg protein. SDS-PAGE showed that the purified CGTase was homogeneous and the molecular weight of the purified CGTase was about 75 kDa. The molecular weight of the enzyme that was estimated by gel filtration under native condition was 79 kDa. This has indicated that Bacillus sp. G1 CGTase is a monomeric protein. The isoelectric point (pI) of the enzyme was about 8.8. Characterization of the enzyme exhibited optimum pH and temperature of 6.0 and 60 8C, respectively. The enzyme was stable from pH 7.0 to 9.0 and retained its high activity up to 60 8C. However, in the presence of 20 mM Ca2+, the purified CGTase is able to prolong its thermal stability up to 70 8C. CGTase was strongly inhibited by ZnSO4, CuSO4, CoCl2, FeSO4, FeCl3 and EDTA. Km and Vmax for the purified enzyme were 0.15 mg/ml and 60.39 mg bcyclodextrin/( ml min), respectively, with soluble starch as substrate. In cyclodextrin production, tapioca starch was found to be the best substrate used to produce CDs. The enzyme produced g- and b-CD in the ratio of 0.11:0.89 after 24 h incubation at 60 8C, without the presence of any selective agents

Thermal Performance Evaluation of a Small-Scale Drying Machine for Palm Oil Mill Sludge

Malaysia is one of the major contributors of palm oil production globally with large amount of palm oil production. This has significantly contributed to large amount of palm oil mill effluent that eventually affect the environment. A small-scale drying machine for palm oil mill is evaluated on its thermal performance to assess the suitability of the machine to produce organic fertilizer from the palm oil mill sludge. Evaluation was performed with computational fluid dynamics simulation and experiment on design configuration options of the drying machine. The effect of air flow to the thermal performance was also studied in conjunction with the design configurations of the drying machine. The results showed promising potential of a design configuration over another in term of thermal performance and functionality

Thermal Performance Evaluation of a Small-Scale Drying Machine for Palm Oil Mill Sludge

Malaysia is one of the major contributors of palm oil production globally with large amount of palm oil production. This has significantly contributed to large amount of palm oil mill effluent that eventually affect the environment. A small-scale drying machine for palm oil mill is evaluated on its thermal performance to assess the suitability of the machine to produce organic fertilizer from the palm oil mill sludge. Evaluation was performed with computational fluid dynamics simulation and experiment on design configuration options of the drying machine. The effect of air flow to the thermal performance was also studied in conjunction with the design configurations of the drying machine. The results showed promising potential of a design configuration over another in term of thermal performance and functionality

Pengaruh Waktu Pengeringan Dan Tempering Terhadap Mutu Beras Pada Pengeringan Gabah Lapisan Tipis

The aim of this research was to determine the effect of various drying and tempering durations on rice quality using thin layer drying. The drying procedure consist four satge; first rough rice was dried in a drying chamber for various durations to remove 5 to 8 % moisture content (M.C). In the second stage rice was tempered under the room temperature for certain duration, to reduce MC gradients within the kernels. tempering period. The rice was then dried further to reach the final 14 % M.C. After the second drying the rice was tempered. Drying process was conducted using  heated air at temperature of either 50 0C, RH 26%  or  60 0C, RH 17%. The results  show that very small  reduction in Head Rice Yield (HRY) when  less than 6 % m.c, were removed during the first drying stage. Effects on HRY was obeserved when the moisture removal was greater than 6% m.c. during the 1st drying stage. It was also observed that tempering time could not prevent the reduction in HRY when moisture remomal was higher than 6% M.C. during the 1st drying stage

Near-real-time Biomonitoring of Heavy Metals Using the Xenoassay® System

Heavy metals have widespread industrial uses and have been found in increasing quantities as contaminants in all components of the biosphere. Water and sediment of rivers near industrial areas such as the Juru River in Penang and Langat River in Selangor are polluted with heavy metals. Thus, rapid and fast methods to detect the presence of heavy metals in the environment are necessary. Existing instrumental methods such as atomic absorption and emission spectrometry are very sensitive but the sole use of these instruments for heavy metal detection is extremely expensive, needs a skillful person to operate and is not amenable to near-real-time analysis. The best scenario for routine biomonitoring of heavy metals is the marriage between instrument- and bioassays. Currently, the USEPA has recognized whole cell-based bioassays such as as PolytoxTM and Microtox® for the detection of heavy metals. Unfortunately these cell-based assays cannot be used as real-time or near real-time assays in the field as they require bulky incubators. Near-real-time monitoring of heavy metals giving results in less than one hour is very useful in environmental CSI (Criminal Scene Investigation) or ECSI where temporal and spatial concentrations of heavy metals in running waters are a challenge to environmentalists to pinpoint heavy metals POS (point of source) for legal purposes. Enzyme-based inhibitive assays are simple, rapid and fast and could be developed for near real-time assays. We have developed an inhibitive assay system –Xenoassay® based on proteases for the assay of heavy metals. The system could detect the heavy metals mercury, cadmium, lead, copper, zinc and silver at the sub parts per million level. Field trial near-real-time assay capability shows promising results

Axial Compression Behaviour of Full-Scale Prefabricated Wood-Wool Wall Panel

This study aims to investigate an axial compression behaviour of prefabricated wall constructed using wood-wool cement composite panel (WWCP). A total of three full scale wall specimens were fabricated at the laboratory with dimension of 2400 mm width, 2400 mm height and 147 mm thickness. The new fabrication technique namely as cross laminated technique was considered where the walls is fabricated using two layers of 600 mm x 2400 mm x 50 mm thickness of WWCP strips, where each layer consists of four panel strips that were arranged at cross wise panel orientation. The front and rear panel strips were bonded together using 15 mm thickness of mortar paste and as a finishing 16 mm thickness of mortar base plaster were applied on both surfaces. The prefabricated wall specimens were tested under axial compression load up to failure after 28 days of curing period. The axial load carrying capacity, vertical and lateral displacement and failure mode behaviour of walls were observed during and after test conducted. The results of experimental testing recorded that; the maximum axial compression load of prefabricated wood-wool wall specimens achieved the capacity of 1038.54 kN. This shows that the new prefabricated wall constructed using cross laminated wood-wool panel can be used as a load bearing wall system for low rise building

Carbonized rice husk and cocopeat as alternative media bed for aquaponic system

The study evaluates the suitability of carbonized rice husk and cocopeat substrates as alternative media bed in aquaponics unit for cultivation of red Nile tilapia and Gynura procumbens. Area occupied by the aquaponics unit is about 4.5 m2 and it was operated under equatorial climate conditions. Various substrates namely lightweight expanded clay aggregate (LECA), cocopeat, carbonized rice husk and a mixture of cocopeat-rice husk at ratio 1:1 were prepared using polybags for growing of the longevity spinach. The resultant effects from fish cultivation and plants growth on the water qualities and nitrification efficiency of the aquaponics unit were reported. The aquaponics unit were operated for twelve weeks and the values of pH, temperature, and dissolved oxygen level were measured to be within the range of 6.4-6.9, 27.7-29oC, and 5.5-7 mg·L-1, respectively. Survival rate for fish was 98% with specific growth rate (SGR) and food conversion ratio (FCR) of 6.9% per day and 1.13, respectively. Nutrient deficiency was not evident and plants showed healthy growth with harvest yield ranging between 3.6 and 3.9 kg·m-2. Results attained signified the suitability of utilizing carbonized rice husk and cocopeat as alternatives media bed compared to commercial media bed such as LECA

Stiffness modulus properties of hot mix asphalt containing waste engine oil

This study presents the effect of waste engine oil (WEO) on the mechanical properties of hot mix asphalt mixtures. It was added into mixture at 0%, 3%, 5%, 7%, 10% and 15% by weight of binder. The mechanical properties of the mixes were evaluated by conducting indirect tensile stiffness modulus (ITSM) at temperatures of 25C and 40C. The results indicated that modified mixes exhibited lower stiffness modulus with the increasing amount of WEO as well as testing temperature. The increasing amount of WEO was found to have a good linear correlation to the decreasing of stiffness modulus. The finding showed that the WEO has the significant role as a softening agent which affected the stiffness modulus even at low percentage