Potential utilization of Microcystis sp. for biodiesel production: green solution for future energy crisis

Authors: Tharindu Madhusanka and Pathmalal Manage
Journal: Asian Journal of MicrobiologyBiotechnology & 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.


Bioremediation of microcystins by two native bacteria: Bacillus cereus and Rahnella aquatilis

Authors: Sumaiya Idroos and Pathmalal Manage
Journal: Asian Journal of MicrobiologyBiotechnology & 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.


Field visit to water treatment plants, Ruhunupura, Sagama, Kondawattuwan and Kanthale.

Students following the course unit Aquatic Microbiology and Water Quality (ARM 103 1.0) had a three day field visit on 5th to 7th May, 2018 to study the water treatment process, strategies and solutions. They had a hands on experience on different practices following under different conditions.  Had a nice relax time with “Kawadi” at Katharagama and water games at Pasikuda beach.