ABSTRACT
Microalgae have been known for broad spectrum of ecological and industrial applications. However, continuous mass culturing of microalgae is still a challenging task. In this context, studies on optimization of culturing conditions like photoperiod and light intensity on nutrients consumption are not uncommon. In the present study, we tried to evaluate the effect of different photoperiod (PP) and photosynthetic photon flux intensity (PPFI) on the nutrient consumption and algal growth of Picochlorum maculatum in shrimp culture effluent. The experiment lasted for 15 days at five different PP cycles (24:0, 18:06, 14:10, 10:14 and 6:18 h light:dark) and four PPFI (50, 100, 150 and 200 µmol m-2 s-1) at 28ºC temperature. Every five days the samples were analyzed and results showed that the PP of 18 h light and 6 h dark and 150 µmol m-2 s-1 of PPFI favouring the growth of P. maculatum with a maximum nutrients consumption (PO43+ 91%, NO3- 68%, NO2- 64%, NH3+ 77%), maximum growth (0.876±0.001 abs) and biomass production (9.93±0.19 g L−1) with highest yield of 9.2% total lipid. Among the photoperiod and photosynthetic photon flux intensity tested, 18:6 h light:dark and 150 µmol m-2 s-1 showed the highest nutrients removal and algal growth. This study strongly suggests that P. maculatum PSDK01 was a potential candidate for further commercial development in larger scale
ABSTRACT
Totally 30 actinobacteria isolates were screened for their larvicidal activity against Anopheles mosquito larvae. Of them four isolates producing strong larvicidal activity. These isolates were morphologically characterized and identified as the isolate CC17, SM13 as Streptomyces sp, isolate SH15 as Streptosporangium, isolate S22 as Micropolyspora. The present investigation clearly reveals the larvaicidal potentials of selected actinobacterial isolates in the Muthupet mangrove soil and sediments. To exploit these findings for humanwelfare, it is necessary to carryout field trial and strategies for optimizing of large scale production of cellbiomass and larvicidal compounds are suggested as future course of action.
ABSTRACT
Study of marine organisms for their bioactive potential, being an important part of marine ecosystem, has picked up the rhythm in recent years with the growing recognition of their importance in human life. Investigation was carried out to isolate 32 strains of endo and epiphytic bacteria in 2 seagrass species viz., Syringodium isoetifolium and Cymodocea serrulata. Morphologically different bacterial strains were tested against 5 antibiotic resistant human bacterial pathogens, of which 10 associated bacteria shown inhibitory activity against one or more bacterial pathogens. Minimum inhibitory concentration (MIC) and Minimum bacterial concentration (MBC) determination with extracellular bioactive compounds from the associated bacteria reveals that, the strain ENC 5 showed inhibitory activity against all the bacterial pathogens with the maximum sensitivity against Pseudomonas aeruginosa at the MIC value of 500 µg ml-1.