Enzymatic transesterification of Jatropha oil

<p>Abstract</p> <p>Background</p> <p>Transesterification of Jatropha oil was carried out in t-butanol solvent using immobilized lipase from <it>Enterobacter aerogenes</it>. The presence of t-butanol significantly reduced the negative effects caused by both methanol and glycerol. The effects of various reaction parameters on transesterification of Jatropha oil were studied.</p> <p>Results</p> <p>The maximum yield of biodiesel was 94% (of which 68% conversion was achieved with respect to methyl oleate) with an oil:methanol molar ratio of 1:4, 50 U of immobilized lipase/g of oil, and a t-butanol:oil volume ratio of 0.8:1 at 55°C after 48 h of reaction time. There was negligible loss in lipase activity even after repeated use for seven cycles.</p> <p>Conclusion</p> <p>To the best of our knowledge this is the first report on biodiesel synthesis using immobilized <it>E. aerogenes </it>lipase.</p

Sinteza izoamilnog acetata pomoću lipaze u sustavu bez otapala s vinilnim acetatom kao donorom acila

Synthesis of isoamyl acetate, a flavour ester extensively used in food industry, has been carried out in a solvent-free system. In the present study, an attempt has been made to enhance the isoamyl acetate synthesis yield by transesterification of isoamyl alcohol with vinyl acetate using immobilized Rhizopus oryzae NRRL 3562 lipase. In the present synthesis, substrates had no inhibitory effect on immobilized lipase. The effects of various reaction parameters on isoamyl acetate synthesis were studied and maximum conversion was achieved at 16 % (by mass per volume) of immobilized lipase, 40 °C and 200 rpm. Under these conditions, 8-hour reaction time was sufficient to reach a high ester conversion of 95 % with 0.5 mol/L of isoamyl alcohol. The structure of the transesterified product was confirmed by infrared and nuclear magnetic resonance spectroscopic studies. Immobilized lipase had Km and vmax values of 306.53 mmol/L and 99 µmol/(h·g) respectively, for isoamyl acetate synthesis in a solvent-free system.Provedena je sinteza izoamilnog acetata, estera koji se često koristi kao pojačivač okusa u prehrambenoj industriji, u sustavu bez otapala. Pokušao se poboljšati prinos izoamilnog acetata transesterifikacijom s vinilnim acetatom pomoću imobilizirane lipaze izolirane iz soja Rhizopus oryzae NRRL 3562. Pri tome supstrat nije inhibirao imobiliziranu lipazu. Istražen je utjecaj različitih parametara reakcije na sintezu te ustanovljeno da je maksimalna pretvorba postignuta sa 16 % (m/V) imobilizirane lipaze pri 40 °C i 200 rpm. Pri tim je uvjetima nakon 8 sati postignuta 95 %-tna konverzija s 0,5 mol/L izoamilnog acetata. Struktura produkta utvrđena je infracrvenom spektroskopijom i nuklearnom magnetskom rezonancijom. Imobilizirana lipaza imala je Km vrijednost od 306,53 mmol/L i υmax od 99 µmol/(h∙g)

Effects of dielectric gradients‐mediated ions partitioning on the electrophoresis of composite soft particles: An analytical theory

International audienceIn this work, we report original analytical expressions defining the electrophoretic mobility of composite soft particles comprising an inner core and a surrounding polymer shell with differentiated permeabilities to ions from aqueous background electrolyte and to fluid flow developed under applied DC field conditions. The existence of dielectric permittivity gradients operational at the core/shell and shell/solution interfaces is accounted for within the Debye-Hückel approximation and flat plate configuration valid in the thin double layer regime. The proposed electrophoretic mobility expressions, applicable to weakly to moderately charged particles with size well exceeding the Debye layer thickness, involve the relevant parameters describing the particle core/shell structure and the electrohydrodynamic features of the core and shell particle components. It is shown that the analytical expressions reported so far in literature for the mobility of hard (impermeable) or porous particles correspond to asymptotic limits of the more generic results detailed here. The impacts of dielectric-mediated effects of ions partitioning between bulk solution and particle body on the electrophoretic response are further discussed. The obtained expressions pave the way for a refined quantitative, analytical interpretation of electrophoretic mobility data collected on soft (nano)particles (e.g. functionalized dendrimers, multilayered polyelectrolytic particles) or biological cells (e.g. viruses) for which the classical hard core-soft shell representation is not appropriate

A novel multi-attribute decision making approach for selection of appropriate product conforming ergonomic considerations

Ergonomic design of a product considers design, cognitive and behavioral information during the design stage with a view to improve the comfort level of the user and aesthetic look of the product. However, a large number of products are available in the market place possessing a wide range of features to address the ergonomic considerations. Many times, the features may be redundant and hardly enhance interaction between the user and the product leading to user dissatisfaction. But few important features focusing its functionality and physical comfort can possibly address the usability of product and improve satisfaction level of the user. This paper proposes a fuzzy multi-attribute decision making (MADM) approach integrating both subjective and objective weights for each criterion so that superior ergonomically designed product can be evaluated. The methodology is explained with the help of an example of selection of an office chair. Three popular approaches have been considered to compare the ranking of alternatives. Keywords: Multi-attribute decision making (MADM), TOPSIS (Techniques for Order Preference by Similarity to Identical Solution), VIKOR (VIseKriterijumska Optimizacija I Kompromisno Resenjea), PROMETHEE (Preference Ranking Organization Method for Enrichment Evaluations

Knowledge, practices and precaution regarding COVID-19 among the residents of Kolkata city, West Bengal, India

Background: Corona virus disease 2019 (COVID-19) has been declared a global public health emergency affecting thousands of people across the world. The knowledge, attitude and practice related to the transmission and prevention of COVID-19 are regarded as the most critical and effective control measures. Therefore, the purpose of this study was to assess the knowledge of, attitude to along with precautionary practices related to COVID-19 adopted by the people of the city of Kolkata, the capital of West Bengal.Methods: A cross-sectional survey was conducted by the interview method through a telephone conversation-based study from July to October 2020. The responses (n=321) were collected using a non-random convenience sampling method. All data were analysed through SPSS software (Ver. 27).Results: A total of 321 participants were included in the present study. Gender, education, and occupation-wise, statistically significant mean knowledge, practices, and overall score differences were found (p&lt;0.001 and &lt;0.05). People without literacy were found to had lesser knowledge (35.1%) and adopted fewer preventive practices and precautionary measures (32.4%). This section also scored lower in overall scores (48.6%) than others. Males scored better in terms of knowledge and practices compared to females; statistically, the gender-wise association was found to be significant (p&lt;0.001 and&lt;0.05).Conclusions: The present study demonstrates a moderate level of knowledge and a significantly high practice (41.4% and 60.7%) about COVID-19 among the study participants. Males have higher knowledge and adopted more preventive practices and precautions than females, and the overall score is high in respect of males as compared to females

Lipase Mediated Isoamyl Acetate Synthesis in Solvent-Free System Using Vinyl Acetate as Acyl Donor

Synthesis of isoamyl acetate, a flavour ester extensively used in food industry, has been carried out in a solvent-free system. In the present study, an attempt has been made to enhance the isoamyl acetate synthesis yield by transesterification of isoamyl alcohol with vinyl acetate using immobilized Rhizopus oryzae NRRL 3562 lipase. In the present synthesis, substrates had no inhibitory effect on immobilized lipase. The effects of various reaction parameters on isoamyl acetate synthesis were studied and maximum conversion was achieved at 16 % (by mass per volume) of immobilized lipase, 40 °C and 200 rpm. Under these conditions, 8-hour reaction time was sufficient to reach a high ester conversion of 95 % with 0.5 mol/L of isoamyl alcohol. The structure of the transesterified product was confirmed by infrared and nuclear magnetic resonance spectroscopic studies. Immobilized lipase had Km and vmax values of 306.53 mmol/L and 99 µmol/(h·g) respectively, for isoamyl acetate synthesis in a solvent-free system

Lipase mediated isoamyl acetate synthesis in solvent-free system using vinyl acetate as acyl donor

Synthesis of isoamyl acetate, a flavour ester extensively used in food industry, has been carried out in a solvent-free system. In the present study, an attempt has been made to enhance the isoamyl acetate synthesis yield by transesterification of isoamyl alcohol with vinyl acetate using immobilized Rhizopus oryzae NRRL 3562 lipase. In the present synthesis, substrates had no inhibitory effect on immobilized lipase. The effects of various reaction parameters on isoamyl acetate synthesis were studied and maximum conversion was achieved at 16 % (by mass per volume) of immobilized lipase, 40 °C and 200 rpm. Under these conditions, 8-hour reaction time was sufficient to reach a high ester conversion of 95 % with 0.5 mol/L of isoamyl alcohol. The structure of the transesterified product was confirmed by infrared and nuclear magnetic resonance spectroscopic studies. Immobilized lipase had Km and vmax values of 306.53 mmol/L and 99 μmol/(h·g) respectively, for isoamyl acetate synthesis in a solvent-free system