Category Archives: Publications

Authors: Tharindu Madhusanka and Pathmalal Manage
Journal: Asian Journal of Microbiology, Biotechnology & Environmental Sciences.

There is a growing concern on the use of alternative sustainable energy source to overcome the energy crisis. Hence, biodiesel from cyanobacteria has drawn the attention of the scientific community. The present study was carried out to find potential utilization of Microcystis bloom for biodiesel production. Microcystis bloom samples were collected from Beira Lake, Sri Lanka and Soxhlet extraction method with Isopropanol: n-hexane (3:2) solvent system was employed to extract lipids. In the present study,biodiesel B6 blend was prepared and the properties of B6 blend were compared with ASTM D 7467(American Society for Testing and Materials standard for B6 – B20 Biodiesel blends)and Ceylon Petroleum Corporation specifications for no: 02-grade auto diesel to confirm the fuel properties and the usability respectively. Biodiesel B6 blend was subjected to determination of fuel properties and density at 15oC (ASTM D 1298/ 4052), Viscosity Kinematic at 60oC (ASTM D 445), Calorific value (Gross) (ASTM D240), Cloud point (ASTMD 2500), Lubricity (HFRR wear sear dia at 60oC) (ASTM D 6079), Sulphur content (ASTM D 4294) and CFPP (Cold Filter Plugging Point) value (ASTM D 6371) were 831.00kg/m3, 2.83cSt., 11180.00kcal/kg, 6oc,405.00μm, 2310.00ppm and 4oC. The results revealed that biodiesel B6 blend complied with ASTM standards for lubricity, kinematic viscosity and sulfur content (S5000). The fuel properties of kinematic viscosity, density, sulfur content and CFPP value complied with the Ceypetco auto diesel specifications and the energy content of the blend was higher than Ceypetco auto diesel specifications. The results of the present study revealed that the Microcystis bloom can be utilized as a potential candidate to produce biodiesel.

Authors: Sumaiya Idroos and Pathmalal Manage
Journal: Asian Journal of Microbiology, Biotechnology & Environmental Sciences.

Microcystins (MCs) are a group of cyclic heptapeptide hepatotoxins produced by cyanobacteria. Among 70 analogues of MCs, Microcystin-LR (MC-LR) is the dominant type in Sri Lankan water bodies. Contamination of MC-LR in drinking water is a serious health issue. Thus, the present study was carried out to identify freshwater bacteria, which are capable of degrading MC-LR. BIOLOG MT2 plate assay was employed to confirm MC-LR biodegradation by the bacterium Bacillus cereus and Rahnella aquatilis which were isolated from Girandurukotte reservoir and form Ulhitiya reservoir respectively. Classic batch culture experiments showed that B. cereus and R. aquatilis removed 100% of MC-LR at 28oC within 8 and 10 days of incubation respectively. Optimized biodegradation conditions for MC-LR by B. cereus and R. aquatilis were recorded at 320C when phosphates and nitrate concentrations were 0.01ppm and 0.4 ppm respectively in experimental medium. Moreover, B. cereus andR. aquatilis were capable of degrading other MCs analogues; Microcystin-LF (MC-LF), Microcystin –LW (MC-LW), Microcystin –RR (MC-RR) and nodularin (NOD) as well. Molecular studies confirmed that B. cereus and R. aquatilis harbored MC degrading mlrA, mlrB, mlrC and mlrD genes. This is the first record for degradation of MCs and NOD by R. aquatilis.

Authors: Sonali Garg, Gayani Senevirathne, Nayana Wijayathilaka, Samadhan Phuge, Kaushik Deuti, Kelum Manamendra-Arachchi, Madhava Meegaskumbura, SD Biju

Journal: Zootaxa

Based on a recent molecular phylogenetic study, the South Asian microhylid genus Uperodon (subfamily Microhylinae) currently comprises of 12 valid species that are largely restricted to India and Sri Lanka. Considering the revised generic-level status of its various members, here we review the taxonomy of all known species in this genus and clarify their nomenclatural status and geographical distribution, by integrating evidence from genetics, adult and tadpole morphology, breeding ecology, and bioacoustics. Our molecular analyses of a mitochondrial 16S rRNA gene fragment combined with external and internal morphological studies also revealed a distinct new species in the genus. This species, formally described as Uperodon rohani sp. nov., is endemic to Sri Lanka and widely distributed at lower elevations in the island. For nomenclatural stability of various previously known members, the following actions are also undertaken: (1) redescription of the poorly-defined species Ramanella anamalaiensis Rao (= Uperodon anamalaiensis) and Hylaedactylus montanus Jerdon (= Uperodon montanus); (2) neotype designation for Ramanella anamalaiensis Rao (= Uperodon anamalaiensis), Ramanella minor Rao, Ramanella mormorata Rao (= Uperodon mormorata), and Ramanella triangularis rufeventrisRao; (3) lectotype designation for Callula variegata Stoliczka (= Uperodon variegatus); and (4) synonymization of Ramanella minor Rao with Uperodon anamalaiensis.

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Authors: Yong Chang Jang, R.R.M.K.P. Ranatunga, Jin Yong Mok, Kyung Shin Kim, Su Yeon Hong, Young Rae Choi, A.J.M. Gunasekara

Journal: Marine Pollution Bulletin

This study provides the first assessment of marine debris washed ashore on 22 beaches along the coast of Sri Lanka. There was an average of 4.1 large (>25 mm) and 158 small (5–25 mm) pieces of debris per square meter of beach. Classified by use, packaging material (55%) dominated the debris, followed by consumer products (25%) and fishing gear (20%). In terms of materials, plastic was the greatest contributor (93%) to marine debris. Beaches near a river mouth or city and those with a barrier had greater debris accumulations. The east coast had significantly greater small debris density, possibly due to strong northeastern monsoon currents. Large spatial heterogeneity was observed in the amount of debris. Long-term monitoring is imperative to better understand the temporal changes in, and the pathways and possible management of, marine debris.

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