Some characteristics of lipases from thermophilic fungi isolated from palm oil mill effluent

Rhizopus oryzae and Rhizopus rhizopodiformis are thermophilic fungi isolated from palm oil mill effluent (POME). They are able to grow up to 50°C and produce remarkable amounts of extracellular lipases. The extracellular lipases from both fungi displayed quite similar characteristics. The optimum pH and temperature for both lipases were 6.0 and 45°C, respectively. However, lipase from R. rhizopodiformis was slightly more thermostable than that of R. oryzae lipase but the latter was more stable over broader pH ranges compared to the former, specially at acidic pH. Both the enzyme showed rapid loss of activities at temperatures above 50°C and pH above 7.0. Lipase from R. oryzae showed broader specificities to substrates than R. rhizopodiformis, but both displayed little reactivity for triacetin and polyoxysorbitan (Tween 20, 40, and 60). Both the lipases are 1,3 specific

Internet usage behaviors among young teenagers

This study identifies the Malaysian suburban young teenagers’ behavior on internet usage: types of information, online activities, and internet topic of interest. This study also investigates the relationship between gender and internet usage behavior. A set of 350 questionnaires have been distributed to a group of young teenagers’ age 11-12 years old in Year Six of primary schools in suburbs of Selangor. A total of 297 completed responses have been received and analyzed using Microsoft Excel and SPSS. The findings indicate that although young teenagers at suburban prefer to search entertainment information, do leisure activities and are interested in non-serious topic, most of the time, they still search information, do online activities and interested on educational information at other time. Further research can be conducted on information content preferences of young teenagers in other parts of Malaysia

Extra- and intra-cellular lipases from a thermophilic Rhizopus oryzae and factors affecting their production

A thermophilic Rhizopus oryzae was isolated, and parameters affecting its production of extra- and intra-cellular lipases were investigated. All carbon sources tested with the exception of sucrose generally inhibited the production of extracellular lipase, but enhanced the production of intracellular lipase. Peptone was the best substrate for extracellular enzyme production, but for intracellular lipase production other substrates such as tryptone, tryptic soy digest, polypeptone, and corn steep liquor gave comparable results. Among lipid substrates, glycerol was the only stimulator of extracellular enzyme production, whereas olive oil, triolein, and oleic acid had very positive effects on intracellular enzyme production. Shaking enhanced the production of both types of enzymes; the temperature optima were 45 and 37°C for extra- and intra-cellular lipases, respectively. A pH of 5.0 was optimal for production of both enzymes

A Comparison between Various Polymeric Membranes for Oily Wastewater Treatment via Membrane Distillation Process

Oily wastewater (OW) is detrimental towards the environment and human health. The complex composition of OW needs an advanced treatment, such as membrane technology. Membrane distillation (MD) gives the highest rejection percentage of pollutants in wastewater, as the membrane only allows the vapor to pass its microporous membrane. However, the commercial membranes on the market are less efficient in treating OW, as they are prone to fouling. Thus, the best membrane must be identified to treat OW effectively. This study tested and compared the separation performance of different membranes, comparing the pressure-driven performance between the membrane filtration and MD. In this study, several ultrafiltration (UF) and nanofiltration (NF) membranes (NFS, NFX, XT, MT, GC and FILMTEC) were tested for their performance in treating OW (100 ppm). The XT and MT membranes (UF membrane) with contact angles of 70.4 ± 0.2° and 69.6 ± 0.26°, respectively, showed the best performance with high flux and oil removal rate. The two membranes were then tested for long-term performance for two hours with 5000 ppm oil concentration using membrane pressure-filtration and MD. The XT membrane displayed a better oil removal percentage of >99%. MD demonstrated a better removal percentage; the flux reduction was high, with average flux reduction of 82% compared to the membrane pressure-filtration method, which experienced a lower flux reduction of 25%. The hydrophilic MT and XT membranes have the tendency to overcome fouling in both methods. However, for the MD method, wetting occurred due to the feed penetrating the membrane pores, causing flux reduction. Therefore, it is important to identify the performance and characteristics of the prepared membrane, including the best membrane treatment method. To ensure that the MD membrane has good anti-fouling and anti-wetting properties, a simple and reliable membrane surface modification technique is required to be explored. The modified dual layer membrane with hydrophobic/hydrophilic properties is expected to produce effective separation in MD for future study

Analisis keberkesanan projek bersepadu dalam penerapan kemahiran generik

Jabatan Kejuruteraan Kimia dan Proses (JKKP), Fakulti Kejuruteraan dan Alam Bina, Universiti Kebangsaan Malaysia telah mengambil satu initiatif untuk melaksanakan Projek Bersepadu (PB) bagi pelajar Tahun II dan III sejak Sesi 2006/2007 sebagai satu langkah untuk meningkatkan lagi mutu proses pengajaran dan pembelajaran terhadap pelajar. Projek ini menggabungkan tiga atau empat kursus wajib jabatan yang ditawarkan bagi setiap semester. Projek bersepadu yang diberikan kepada pelajar ini merupakan permasalahan kejuruteraan kimia/biokimia yang memerlukan penyelesaian terbuka. Pendekatan ini membolehkan penerapan kemahiran generik terhadap pelajar seperti kepimpinan, bekerja dalam kumpulan, berkomunikasi secara lisan dan bertulis serta belajar mencari maklumat terkini melalui proses pembelajaran sepanjang hayat. Pencapaian pelajar dalam menyiapkan PB telah diukur dan dinilai melalui pembentangan lisan dan laporan bertulis. Kajian ini dilakukan bagi mengukur keberkesanan PB setelah empat tahun dilaksanakan di JKKP. Oleh itu, satu soal selidik telah diagihkan kepada kumpulan pelajar pertama yang telah mengharungi sepenuhnya PB di sepanjang pengajian di JKKP dalam satu majlis ramah mesra sebaik mereka tamat perkuliahan mereka. Keputusan analisis terhadap keberkesanan PB telah menunjukkan peningkatan keyakinan diri dalam kemahiran generik seperti komunikasi lisan dan penulisan, kerja berkumpulan, pembelajaran sepanjang hayat dan pengenalpastian isu-isu semasa dalam diri pelajar semenjak PB diperkenalkan. Maklum balas yang positif juga diperoleh daripada pelajar dan mereka berpendapat PB perlu diteruskan di masa akan datang kerana PB amat membantu mereka dalam menjalankan projek reka bentuk di tahun akhir pengajian mereka