Valorization of biomass to hydroxymethylfurfural, levulinic acid, and fatty acid methyl ester by heterogeneous catalysts

Biodiesel production from sunflower oil over MgO/MgAl2O4 nanocatalyst: Effect of fuel type on catalyst nanostructure and performance

Biodiesel has provided an eco-friendly solution to fuel crisis, as it is renewable, biodegradable and a non-toxic fuel that can be easily produced through enzymatic transesterification of vegetable oils and animal fats. Enzymatic production of biodiesel has many advantages over the conventional methods as high yields can be obtained at low reaction temperatures with easy recovery of glycerol. Microbial lipases are powerful biocatalysts for industrial applications including biodiesel production at lower costs due to its potential in hydrolyzing waste industrial materials. Among them, lipases from yeasts, Candida antarctica, Candida rugosa, Cryptococcus sp., Trichosporon asahii and Yarrowia lipolytica are known to catalyze such reactions. Moreover, stepwise addition of methanol in a three step, two step and single step reactions have been developed using yeast lipases to minimize the inhibitory effects of methanol. The latest trend in biodiesel production is the use of whole-cell as biocatalysts, since the process requires no downstream processing of the enzyme. Synthesis of value added products from the byproduct glycerol further reduces the production cost of biodiesel. This review aims at compiling the information on various yeast lipase catalyzed transesterification reactions for greener production of biodiesel.

Enzymatic transesterification for production of biodiesel using yeast lipases: An overview

Biodiesel from waste frying oils: Methods of production and purification

Valorization of spent coffee grounds into biofuels and value-added products: Pathway towards integrated bio-refinery

Characterization and parametric study of mesoporous calcium titanate catalyst for transesterification of waste cooking oil into biodiesel

In this study, luminescent bio-adsorbent nitrogen-doped carbon dots (N-CDs) was produced and applied for the removal and detection of Hg (II) from aqueous media. N-CDs were synthesized from oil palm empty fruit bunch carboxymethylcellulose (CMC) and urea. According to several analytical techniques used, the obtained N-CDs display graphitic core with an average size of 4.2 nm, are enriched with active sites, stable over a wide range of pH and have great resistance to photobleaching. The N-CDs have bright blue emission with an improved quantum yield (QY) of up to 35.5%. The effect of the variables including pH, adsorbent mass, initial concentration and incubation time on the removal of Hg (II) was investigated using central composite design. The statistical results confirmed that the adsorption process could reach equilibrium within 30 min. The reduced cubic model (R2 = 0.9989) revealed a good correlation between the observed values and predicted data. The optimal variables were pH of 7, dose of 0.1 g, initial concentration of 100 mg/L and duration of 30 min. Under these conditions, adsorption efficiency of 84.6% was obtained. The adsorption kinetic data could be well expressed by pseudo-second-order kinetic and Langmuir isotherm models. The optimal adsorption capacity was 116.3 mg g−1. Furthermore, the adsorbent has a good selectivity towards Hg (II) with a detection limit of 0.01 μM due to the special interaction between Hg (II) and carboxyl/amino groups on the edge of N-CDs. This work provided an alternative direction for constructing low-cost adsorbents with effective sorption and sensing of Hg (II). 

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Ecofriendly adsorption and sensitive detection of Hg (II) by biomass-derived nitrogen-doped carbon dots: process modelling using central composite design

Malachite Green Adsorption by Spent Coffee Grounds

Isolation of vanillin from lignin extracted from coconut husk is presented in this study. Phosphoric acid (20%) is employed to precipitate the lignin from the black liquor produced by cooking the mixture of coconut husk and 1M NaOH in steam autoclave at 121oC for one hour. Separation of vanillin from lignin was carried out via oxidation by adding 0.1 g of coconut husk lignin into a mixture of 2M NaOH (10 ml) and nitrobenzene (0.4 ml) in steel capillary bomb heated at 160oC for 2.5 hours. Detection and quantification of vanillin presents in the lignin oxidized mixture was performed by liquid and gas chromatography. The recovery of vanillin from the mixture was done via crystallization process by dissolving the mixture in acetone and heats up to 60oC with periodic stirring. Vanillin crystal appeared by rapidly cooled the heated mixture in the ice bath. The vanillin obtained was characterized by Infrared Spectroscopy (FTIR) for component verification. Component isolation by HPLC and GC-FID denoted the retention time of vanillin appeared around 18.852 minutes and 16.913 minutes respectively. A yield of 2.83 % vanillin was isolated from 0.1 g lignin sample and the result of FTIR characterization has suggested that the isolated compound is vanillin.

Isolation and Characterization of Vanillin from Coconut Husk Lignin via Alkaline Nitrobenzene Oxidation

Utilization of lignocellulosic biomass as the source for lignin could possibly gain an interest and future demands due to its potential to be converted into high value added compound based on their structural characteristics. Three types of biomass lignin originated from oil palm empty fruit bunch fiber (OPEFB), coconut husk and kenaf fibers are subjected to an alkaline hydrolyzation in steam autoclave and precipitation by phosphoric acid. The structural characterization of all three lignin samples performed by FTIR spectroscopy and HNMR analysis suggests that OPEFB is primarily consist of syringyl (S) units while coconut husk and kenaf fiber were consisted of guaiacyl (G) units. However, all three samples exhibit small portion of p-hydroxyphenyl propane (H) units.

Noor Amirah Abdul Halim

Papers

Characterization and parametric study of mesoporous calcium titanate catalyst for transesterification of waste cooking oil into biodiesel

Ecofriendly adsorption and sensitive detection of Hg (II) by biomass-derived nitrogen-doped carbon dots: process modelling using central composite design

Malachite Green Adsorption by Spent Coffee Grounds

Isolation and Characterization of Vanillin from Coconut Husk Lignin via Alkaline Nitrobenzene Oxidation

Monomeric Structure Characterization of Different Sources Biomass Lignin