Isolation and characterization of bioactive compounds in medicinal plant centella asiatica and study the effects on fungal activities

Medicinal plants are sources of important therapeutic aids for alleviating human ailments. The present research investigation was carried out to study anti-fungal activity of C. asiatica were tested against C. albicans, Aspergillus niger, and Penicillium sp. using two methods, disc diffusion method and broth dilution method. C. asiatica crude methanol extract was found to be the most effective against fungal activity. Compared to disc diffusion, broth dilution was a more appropriate method to quantitatively determine the anti-Candida activity of plant extract, whereby the MIC values of the crude extracts was determined. The result from disc diffusion assay demonstrates that plant extracts have an inhibitory effect. However, the broth dilution method result reveal that C. asiatica crude methanol extract has lower MIC values, meaning it has more prove that C. asiatica has an anti-fungal effect. Bioactive analysis results reveled that bioactive compounds present in the leaf, stems, roots, and the whole plant extract from Centella asiatica are the major chemical constituents are n-Hexadecanoic acid (99%), cis-Vaccenic acid (91%), 5-Hydroxymethylfurfural (88%), Tetradecanoic acid (86%). Further study is required to find out the specific phytochemical which is responsible for its medicinal value

Direct interspecies electron transfer performance through nanoparticles (NPs) for biogas production in the anaerobic digestion process

Biogas production can be appreciated as an energy source for humankind, and its role in world biomaterial turnover with billions of tons of methane produced annually by microorganisms. Several nanoparticles (NPs) are used for microbes-tomicrobes communication in enzymatic reactions for waste conversion into bioenergy. In the anaerobic digestion (AD) process, direct interspecies electron transfer (DIET) is a newly discovered step that helps to increase biogas production. The DIET process promotes rapid electron donation/acceptance of microbes that produce higher biogas during the AD process. In DIET, microbial syntrophic growth involves independent electron transfer from one microbe to another without shuttling by forming hydrogen or formate. In the methanogenesis stage, Geobacter metallireducens and Methanoseta showed a positive response for DIET in the presence of different NPs in the AD system. This review focuses on the role of NPs (metallic, carbon, and non-carbon) in DIET and the advantages and disadvantages of NPs in the biogas production process. A membrane surrounded by protein and metallic or nonmetallic NPs in the DIET mechanism has explicitly elaborated on the appearance of metallic conductive pili. In the methane digester, carbon, and non-carbon-based NPs help to interact with microbes to improve the DIET process and biogas production. Finally, the state of the art of implementing various prospective NPs in biogas production to upgrade AD technology for future development

The optimization of oil extraction from macroalgae, Rhizoclonium sp. by chemical methods for efficient conversion into biodiesel

Optimization of biodiesel production from freshwater macroalgae, Rhizoclonium sp. was investigated in this study. Biodiesel production process parameters such as chemical solvent extraction, hexane:ether and different extraction techniques were optimized by using the response surface methodology based on the central composite design. Optimization of the transesterification process was conducted by varying two factors each at three different levels and this required a total of thirteen runs. A quadratic model was created to predict the biodiesel yield where the R2 value was found to be 0.97, which indicates the satisfactory accuracy of the model. Based on the results, the optimum process parameters for transesterification of the macroalgae Rhizoclonium sp. oil mixture at an agitation speed of 300 rpm over a period of 180 min was found to be a hexane:ether molar ratio 1:1(40 mL), NaOH catalyst concentration of 1 wt% and reaction temperature of 45 °C. Finally, a process optimization found highest macroalgae oil by simple treatment was 0.376 ± 0.14 g and ultrasonic treatment was 6.044 ± 0.81 g is the highest of biodiesel weight. For transesterification reaction from macroalgae oil, a triglyceride was mixed with 0.25 g methanol converted to biodiesel into methyl esters. The biodiesel weight 0.174 ± 0.034 g and 82.2% of the total fatty acid methyl esters (FAME) were confirmed from gas chromatography (GC) analysis. The biodiesel properties were characterized and the results obtained. Design-Expert Version 11 was used to draw both 3D surface plots and 2D contour plots to predict the optimum biodiesel yield

A selective microalgae strain for biodiesel production in relation to higher lipid profile

Biodiesel have become the important asset by the country especially to build up their economy. Currently, microalgae have been choosing as the source for production of biodiesel based on their advantages. Microalgae are a photosynthetic organism that use light as an energy source and able to produce their own food. These microalgae also produce a lipid that can be used to produce a biodiesel. Using microalgae that contain high lipid profile are very important to make sure the biodiesel can be produce in large quantity in short time and more cost saving. Although many microalgae species have been identified and isolated for lipid production, there is currently no consensus as to which species provide the highest productivity. Different species are expected to function best at different aquatic, geographical and climatic conditions. So, this experiment is conducted to identify which strain of microalgae contains high lipid profile that can be used to convert into the biodiesel. There are three main objectives that involve in this experiment which is to isolate and identify different strain of microalgae from Kuantan Coast, East Coast Peninsular Malaysia, to convert the lipid from microalgae into biodiesel through transesterification, and to estimate higher lipid profile of microalgae species for biodiesel production. Two species of green microalgae were isolated, which is Nannochloropsis sp and Coelastrum sp. Based on lipid extraction and lipid analysis, it shows that the Nannochloropsis sp. have more concentrated of lipid and higher lipid profile compared to Coelastrum sp. Hence, Nannochloropsis sp. are most suitable species that can be used as a biodiesel feedstock due to higher lipid profile of MUFA

Synthesis of silver nanoparticles using marine macroalgae Padina sp. and its antibacterial activity towards pathogenic bacteria

Background: Marine algae used as a food source for ocean life and range in color from red to green to brown grow along rocky shorelines around the world. The synthesis of silver nanoparticles by marine alga Padina sp. and its characterization were fulfilled by using UV-visible spectrophotometer, Fourier transform infrared spectroscopy,scanning electron microscopy and field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy

Effect of Plant Hormones on the Production of Biomass and Lipid Extraction for Biodiesel Production from Microalgae Chlorella Sp.

The economic globalization and rapid energy depletion require alternative forms of energy which is more reliable, sustainable and renewable without causing adverse effects to the life forms. Microalgae are currently considered to be one of the most promising alternative sources for biodiesel and the application of phytohormones has also been considered a promising way to increase the production of lipid from microalgae recently. The present study is aimed to cultivate the algal species, Chlorella as a feedstock and the effect of various concentrations of phytohormones such as 6-Benzylaminopurine (BAP), Gamborg’s b-5 vitamins, Indole-3-butyric acid (IBA), 2, 4-Dichlorophenoxyacetic acid (2,4-D) was used for the production of lipid. The extracted lipid oils were then converted into methyl ester via the transesterification process. Indole-3-butyric acid (IBA) relatively supported the maximum growth of 7.185 g/ ml and the lipid yield was 3.5g/ml. The GC-MS characterization showed many peaks corresponding to the fatty acid methyl esters. Among those Ethylbenzene, o-Xylene, Benzene,1,2,4-trimethyl and Decane peaks of hydrocarbons were found important in the biofuel production. The current study demonstrates that the phytohormone IBA accelerate the microalgae growth and also induce the production of lipid oils for biodiesel production