Browsing by Author "YONG JAW CHUEN"

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    INHIBITIVE CHEMICAL CUE OF Pseudomonas pseudoalcaligene ON BIODEGRADATION OFANTHRACENE IN SEAWATER MEDIUM
    (Journal of Sustainability Science and Management, 2009) HII YII SIANG; LAW AH THEEM; CHUAH LAI FATT; NOOR AZHAR MOHAMED SHAZILI; MOHAMED KAMILABDUL RASHID; YONG JAW CHUEN
    This study aims to reveal the self-inhibitive mechanism of an oil degrading bacteria, Pseudomonas pseudoalcaligene biodegradation of anthracene in seawater. Biodegradation of anthracene by the oil-degrading bacteria was analogue to the Monod equation and exhibited a typical bacterial growth pattern. Biodegradation of anthracene was retarded when the bacteria approached its stationary growth phase. The results indicated that the level of dissolved organic carbon and hydrogen ion in the seawater mediwn increased due to anthracene biodegradation. The organic compounds were believed to be secondary metabolites produced by the oil-degrading bacteria. These metabolites seem to inhibit activities of the oil degrading bacteria. The inhibitive effect was confirmed when the newly inoculated oil degrading bacteria failed to grow in the residue mediwn replenished with nutrients and new carbon source and incubated under optimal condition. It is interesting to note that, this replenished mediwn supported the growth of other non-oil degrading bacteria, Erythrobacter citreus. Presence of E. citreus in the mediwn utilized the inhibitive metabolites and thus reswned activities of the oil degrading bacteria for anthracene. Mixing the oil-degrading bacteria (P. pseudoalcaligenes) and non-oil degrading bacteria (E. citreus) improved biodegradation ofanthracene in the seawater. The bacterial mixture improved anthracene degradation by 36% compared to the oil degrading bacteria alone.
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    SEASONAL VARIATION OF WATER CHARACTERISTICS DURING INTER-MONSOON ALONG THE EAST COAST OF JOHOR
    (Journal of Sustainability Science and Management, 2011) MOHD FADZIL MOHD AKHIR; YONG JAW CHUEN
    Inter-seasonal influence of monsoon on the South China Sea oceanographic condition is apparent. Nonetheless, little information exists on temporal variation in the southeast coast of Peninsular Malaysia especially near Johor. Two cruises have been conducted in two different monsoon seasons, both in October 2004 and March 2005. Accordingly, in this study, we examine the water-characteristics profile of the two periods. The results show that the differences in the hydrographical structures are apparent. In March, lower temperature is recorded with higher salinity than October. The TS diagram also suggests that the water of both periods do not share any similarity. This indicates that the water mass of both seasons might originate from different places. Comparisons with earlier studies suggest that influence of current circulation pattern during monsoon period toward the water profile is believed to be main reason. Additionally, some local effects such as sea surface heat flux and wind stress are also among the factors. This oceanographic seasonal differences described in this study are not only important for the area, but will also provide valuable information for the coastal region of southern South China Sea where the understanding of the temporal variation is lacking.