Microalgae are known as an alternative source of biomass energy to replace fossil fuels. The aim of the present study is to optimise the growth conditions and increase the lipid, carbohydrate and biomass productivity of Tetradesmus obliquus UPSI-JRM02 using response surface methodology with Design Expert software. Four variables (nitrogen concentration, temperature, pH, and light intensity) were optimised to enhance T. obliquus productivity. The highest lipid (33 ± 1.2mg/L/day), carbohydrate (51 ± 1.5 mg/L/day) and biomass (115 ± 1.4 mg/L/day) productivity were produced at a nitrogen concentration of 400 mg/L NO3
at 36 C with pH of 9.8, and light intensity of 23500 lux. The fatty acid methyl ester contains polyunsaturated fatty acid (C18:2, C18:3) and saturated fatty acid (C16:0). These results demonstrate the potential of T. obliquus to produce promising feedstock for biofuel production.  ..

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Study on physico-chemical characteristics of different agricultural land uses in subcatchment of Bernam River was carried out. Five soil sampling stations (S1, S2, S3, S4, and S5) were selected to collect the soil to be tested. Physico-chemical characteristics determined were organic matter content, size particle distribution and total organic carbon. Particle size distribution was determined by pipette method and dry sieving. Organic matter and total organic carbon were measured through loss of ignition and Walkley-Black method respectively. Correlation test on physico-chemical characteristics showed that clay and organic matter content have a positive relation and significance (r=0.809, p..

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The study aims to investigate the effect of photo-autotrophic cultural conditions on the productivity and biomass composition of Chlorella vulgaris. The following five photo-autotrophic cultural conditions were investigated: light intensity (4000, 10,500, 17,000, 23,000, 30,000 lux), temperature (25, 28, 32, 35, 40
C), pH (6, 7, 8, 9, 10), CO2 (0.03, 2.5, 5, 7.5, 10%) and NO3 (0, 250, 500, 750, 1000 mg/L). Results indicate that lipid and protein yields were increased by 3.19 fold and decreased by 1.47 fold, respectively, under NO3 deficiency (0 mg/L). Meanwhile, carbohydrate yield was increased by 1.39 fold in 5% CO2. Further cultivation with parameters of the highest biomass productivity (10,500 lux, 28
C, pH 8, 5% CO2 and 500 mg/L NO3 ) achieved the maximum biomass productivity of 0.468 g/L/day. Moreover, cultivation with parameters of the highest lipid yield (23,500 lux, 40
C, pH 8, 0.03% CO2 and 0 mg/L NO3) achieved the maximum lipid yield of 43.70%. The major fatty acid methyl .....

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In recent years, the development of nanoparticle materials for water treatment has received great attention. From an industrial technological view point, the application of nanomaterials in the twenty-first century for water treatment will be the focal point of advanced materials design, processing and progress. In this context, the potential utilisation of different types of flocculants to clean up contaminated water becomes important to address the tremendous increase of water pollution resulting from continued high-level global industrialisation. A number of researchers have investigated the effectiveness of various nanoflocculants for this purpose. Although these nanoflocculants have been reported to successfully treat contaminated water, their flocculation performances are different. To the best of our knowledge, there is no review article which summarises the application and performance of nanoflocculants in the treatment of water containing various types of contaminants. This re.....

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The  mature  landfill  leachate  is  characterized   by  high-strength   ammonium,  which leads to  difficulties in reducing  the ammonium concentration in the wastewater discharge to the permissible   limit  (10 mg/L)  using the existing  biological  treatment  of sequencing batch  reactors   (SBRs).  The  challenge  of  the  nitrogen  removal  via  nitrification  of  high­ strength   ammonium  landfill  leachate  is  substrate  inhibition,  particularly  in  the  form  of free   ammonia  (FA)  and  free  nitrous  acid  (FNA)  in  ammonia-oxidizing  bacteria  (AOB) and  nitrite-oxidizing bacteria (NOB). The problem is more severe, as 43% of the landfills are  not   well  designed   and   not  properly  equipped   with  leachate  control   mechanism facilities.    In  particular,   this  type  of  landfill   exposed   the  river  water  to  the  risk  of  ammonium  contamination  fr.....

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Nitrogen stress condition is believed to increase the production of lipid in microalgae, but the synthesis of both lipid and carbohydrate is less known. Therefore, the effect of nitrogen stress condition on the synthesis of lipid and carbohydrate of Tetradesmus obliquus UPSI-JRM02 was studied in a 2 L bioreactor system. The highest lipid and carbohydrate yields achieved under nitrogen stress condition were 37% and 23%, respectively. Nitrogen stress condition induced the accumulation of carbohydrate at early stage but started to reduce on day 4 when the carbon shifted towards lipid production. The fatty acid profile produced under nitrogen stress condition was composed of 54% polyunsaturated fatty acid (PUFA), 43% saturated fatty acid (SFA) and 3% monounsaturated fatty acid (MUFA). The biofuel properties of T. obliquus obtained under the nitrogen stress condition was within the range of biodiesel standard and is most suitable for the usage in cold country. ? 2021 Penerbit UTM Press. All.....

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