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Biodiesel Dari Lipid Yang Diekstrak Pada Mikroalga Basah Menggunakan Metode Ekstraksi Dimetil Eter
Full text linkMikroalga berpotensi sebagai raw material untuk memproduksi biofuel (biodiesel, bioetanol dan biogas) karena mengandung kadar lipid yang tinggi yaitu sekitar 4-77 %. Lipid dapat dikonversi menjadi biodiesel melalui reaksi esterifikasi dan transesterifikasi. Penelitian ini dilakukan untuk mempelajari penggunaan dimetil eter (DME) sebagai pelarut untuk mengekstrak lipid dari tiga spesies mikroalga: Nannochloropsis oculata, Nitzschia sp. dan Chaetoceros calcitrans, dimana mikroalga dalam kondisi basah tanpa pretreatment seperti proses drying dan cell disruption. Hasil ekstraksi metode DME kemudian dibandingkan dengan metode ektraksi Sokletasi dan Bligh Dyer. Komponen-komponen lipid yaitu asam lemak bebas (free fatty acid, FFA), monogliserida (monoacylglycerol, MAG), digliserida (diacylglycerol, DAG) dan trigliserida (triacylglycerol, TAG) ditentukan melalui analisa kromatografi gas- flame ionization detector (GC-FID). Lipid dari mikroalga dikonversi menjadi biodiesel menggunakan metode metanol superkritis non-katalik pada suhu 290oC selama 2 jam. Kandungan lipid dari metode ekstraksi DME (akumulasi 5 kali ekstraksi pada suhu 40oC dengan jumlah DME sebanyak 100g) untuk N.oculata, Nitzschia sp. dan C. calcitrans adalah 70.03%, 73.3% dan 60.92% masing-masing. Biodiesel yang disintesis mengandung asam miristat (C14:0), asam palmitat (C16:0) dan asam palmitoleat (C16:1).
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Microalgae have potential as raw materials for biofuel production (biodiesel, bioethanol and biogaseous) because contain high lipid content about 4-77 %. Lipid can be convert to biodiesel via esterification and transesterification reaction. This study performed to investigate the usage of dimethyl ether (DME) as solvent to extract lipid from three species microalgae: Nannochloropsis oculata, Nitzschia sp. and Chaetoceros calcitrans, at wet condition without pretreatment such as drying and cell disruption process. DME extraction results then compare with Soxhlet and Bligh Dyer extraction method. Free fatty acid (FFA), monoacylglycerol (MAG), diacylglycerol (DAG) and triacylglycerol (TAG) as lipid components were determined by gas chromatography-flame ionization detector (GC-FID) analysis. Lipid from microalgae converted to biodiesel using non catalytic supercritical methanol method at temperature 290oC for 2 hours. Lipid content from DME extraction method (accumulation for 5 times extraction at temperature 40 oC for 100g of DME amount) for N.oculata, Nitzschia sp. and C. calcitrans were 70.03%, 73.3% and 60.92% respectively. Biodiesel that has been synthesized contain myristic acid (C14:0), palmitic acid (C16:0) and palmitoleic acid (C16:1).
Keywords : Lipid, Nannochloropsis oculata., Nitzschia sp., Chaetoceros calcitrans, Dimethyl ether, Biodiese
Ekstraksi Komponen Lipid dari Mikroalga Nannochloropsis oculata dan Nitzschia sp. dengan Metode Sokletasi dan Bligh Dyer: Extraction of Lipid Components from Nannochloropsis oculata and Nitzschia sp. Microalgae with Soxhletation and Bligh Dyer Methods
Full text linkDependence on fossil energy sources as non-renewable energy will trigger the threat of an energy crisis in Indonesia in the future. The solution to this issue is through the development of renewable energy and one of them is through the exploration and utilization of biomass such as microalgae. Microalgae have a high lipid content (4-77%) and have potential as raw materials for producing biofuel (biodiesel, bioethanol, and biogas). Lipids can be converted into biodiesel through acid or base-catalyzed esterification and transesterification reactions. The aim of this research was to determine the percentage of lipid components, namely free fatty acids (FFA), monoglycerides (MAG), diglycerides (DAG), and triglycerides (TAG) from microalgae extracts of Nannochloropsis oculata and Nitzschia sp. using Soxhletation and Bligh Dyer extraction methods. This research also aims to determine the comparison of lipid yields from the two extraction methods. Lipid yield percentage was determined through gas chromatography analysis. The research results showed that the percentages of FFA, MAG, DAG, and TAG for N. oculata ranged from 3.34 - 33.79% (soxhletation) and 0 - 17.54% (bligh dyer). Meanwhile, for Nitzschia sp., the percentage ranged from 7.16 - 26.28% (soxhletation) and 0.45 - 13.73% (bligh dyer). Lipid yield for N. oculata was 1.81% (soxhletation) and 2.21% (bligh dyer), while for Nitzschia sp., 0.96% (soxhletation) and 2.10% (bligh dyer). Based on the results of both extraction methods, it was found that the total lipid percentage of the microalgae N. oculata was higher than Nitzschia sp
PRELIMINARY STUDY OF LIPID CONTENT IN BROWN ALGAE (Sargassum binderi) FROM MANOKWARI WATERS
Full text linkAlgae are marine plants that have the potential as raw material for producing biofuel (biodiesel, bioethanol and biogas) apart from being used as biomass. The high lipid content in algae can be converted into biofuel through esterification and transesterification chemical reactions. Research on the chemical composition of algae species found in West Papua remains limited. One type of algae commonly found in the waters of West Papua, especially on the northern coast of Manokwari is Sargassum binderi. Therefore, the aim of this study is to identify the types and percentages of lipid compounds contained in S. binderi. Lipid compounds were extracted using 2 different extraction methods, the maceration method and the Bligh Dyer method. The extraction process uses wet samples of S. binderi without drying, grinding or heating treatments. The type and percentage of lipids were determined via GC-MS analysis. The study results revealed six lipid compounds obtained from the maceration method: tetradecanoic acid (1.4%), 10-octadecenoic acid (4.69%), hexadecanoic acid (19.15%), 9-octadecenoic acid (Z) (5.93%), octadecanoic acid (2.71%), and 5,8,11,14-eicosatetraenoic acid (1.01%), with a total lipid compound percentage of 34.89%. Meanwhile, from the Bligh Dyer method, five lipid compounds were identified: 9-octadecenoic acid (Z) (4.33%), hexadecanoic acid (46.07%), 9,12-hexadecadienoic acid (5.23%), 11-octadecenoic acid (27.18%), and 5,8,11,14-eicosatetraenoic acid (2.81%), with a relatively high total lipid percentage of 85.62%. Hexadecanoic acid, also known as palmitic acid, was the lipid compound with the highest percentage found in both extraction methods
Energy auditing and electricity saving opportunities in BPOM laboratory of manokwari
Full text linkEnergy auditing is a method of increasing energy efficiency. An energy audit is conducted to provide an overview of energy use, analyze the electrical system, and determine potential cost savings. The laboratory of the national food and drug agency (BPOM) in Manokwari has problems with electricity that often cause interruptions, power outages, and expensive bills. Therefore, this research was conducted to audit the energy used in the laboratory of the BPOM of Manokwari, with a building area of 1,484 m2 and an installed power of 105 kVA. In this laboratory building, a diesel generator with capacity of 5 kVA is installed as a backup energy source and the generator has its own installation line. According to the calculation results before auditing, the energy consumption intensity (IKE) value obtained per month is 10.18 kWh. Energy audit through lighting loads and air conditioning systems. Then the recommendation through energy savings for lights and air conditioners is 274.12 kWh/month and 639.32 kWh/month, respectively. Therefore, total savings are 913.44 kWh/month, or about IDR 1,541,886.72/month
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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