Potential of fat, oil and grease (FOG) for biodiesel production: A critical review on the recent progress and future perspectives

Evaluation on feedstock, technologies, catalyst and reactor for sustainable biodiesel production: A review

A review on latest trends in cleaner biodiesel production: Role of feedstock, production methods, and catalysts

Environmentally benign solid catalysts for sustainable biodiesel production: A critical review.

As green catalysts, lipases' productivity, and wide substrate selectivity are preferable over chemical catalysts in biodiesel production. Lipases require milder reaction conditions and produce cleaner downstream products. To ensure practical recovery of lipases for repeated uses in biodiesel production, immobilizing lipases into solid forms has been suggested to complement its efficiency, utility, and sustainability. Immobilization, however, adds to the cost of the already economically inviable lipases. Most immobilization protocols also largely depend on fossil derivatives and produce an ever-increasing amount of waste. Therefore, it has been deemed necessary to delineate a scope for the fundamental success of using immobilized lipases for large-scale biodiesel production. Hence, this review presents a way forward to address immobilized lipase cost by using green chemistry strategies that have shown success in recent studies. A comparison of lipases with other biodiesel catalysts is presented in the early part of this review. Conventional and emerging immobilization protocols are also evaluated. The choice between synthetic and natural polymers for immobilization emphasizes the importance of using green chemistry metrics in addressing reusability, toxicity, resource efficiency, water, and carbon footprint of lipase immobilization. Therefore, this review advances immobilized lipase technology by identifying gaps that can be used by research and industry for its deployment to supplant chemical catalysts currently used in biodiesel production.

Immobilized lipases for biodiesel production: Current and future greening opportunities

Inexpensive but resourceful sources of lipids, for example, used cooking oil (UCO) and brown grease (BG), which often contain large amounts of free fatty acids (FFA), are difficult to convert into biodiesel economically and in good yield. Candida rugosa lipase nanoparticles (cNP) were formed first and subsequently cross-linked nanoparticles (CLNP) were obtained by crosslinking of them. Alternatively, cNP were conjugated to magnetic nanoparticles (mNP) to achieve a cNP-mNP conjugate. All three formulations were employed in three different organic solvents (n-heptane, 1,4-dioxane, and t-butanol) to produce biodiesel using BG and UCO in the transesterification reaction with ethanol and methanol. The radii of nanoparticles (NP) were 5.5, 75, 100, 85 nm for mNP, cNP, CLNP, and cNP-mNP, respectively, as measured by scanning/transmission electron microscopy and dynamic light scattering. The catalytic efficiency (Kcat/KM) of cNP, CLNP, and cNP-mNP was increased ca. -25, -68, -176 folds in n-heptane and -35, -131, -262 folds in 1,4-dioxane compared to the lyophilized lipase in the model transesterification reaction of p-nitrophenyl palmitate (PNPP) with ethanol. In biodiesel formation, the best performance with 100% conversion of BG was achieved under optimum conditions with cNP-mNP, ethanol at a 1:3 molar ratio of lipid-to-alcohol, NP at a 1:0.1 weight ratio of lipid-to-enzyme, and water at a 1:0.04 weight ratio of enzyme-to-water at 30 oC for 35 h. The operational stability of the CLNP and cNP-mNP was sustained even after five consequent biodiesel batch conversions while 50% and 82% residual activity (storage stability) were retained after 40 d.

Candida rugosa lipase nanoparticles as robust catalyst for biodiesel production in organic solvents

We developed a nanoparticulate Rhizopus arrhizus lipase formulation to enhance its activity and to increase the conversion yield of lipids into fatty acid methyl esters (FAME, a.k.a., biodiesel). More than 95% purity of the lipase was achieved in a two-step purification. Nanoparticle formulation was afforded by co-lyophilization of the lipase with methyl-β-cyclodextrin (MβCD), an established lyoprotectant. Scanning electron microscopy and dynamic light scattering measurements showed a size of 75–200 nm for the nanoparticles depending on the ratio of lipase-to-MβCD employed during co-lyophilization. Fourier transform infrared spectroscopic analysis by Gaussian curve fitting of the resolution-enhanced amide I region of lyophilized and nanoparticulate lipase indicated a more native-like secondary structure in the latter. A 98% substrate-to-FAME conversion was achieved in 10 h in n-hexane by lipase nanoparticles, whereas the crude and lyophilized enzyme showed 65 and 70% conversion in 18 h, respectively. In t...

https://pubs.acs.org/doi/pdf/10.1021/acsomega.8b02069

Crystal A. O'Neill

Papers

Candida rugosa lipase nanoparticles as robust catalyst for biodiesel production in organic solvents

Synthesis of Rhizopus arrhizus LipaseNanoparticles for Biodiesel Production