Valorization of Lubrication Oil and Cooking Oil via Catalytic Copyrolysis with Ni Doped on Activated Carbon

The aim of the copyrolysis of used lubricant oil (ULO) and used cooking oil (UCO) was to investigate the effects of operating parameters on the thermal stability of ULO and UCO, which significantly improves the quality of fuel-like products. This process was carried out in a 3000 cm3 semibatch pyrolysis reactor; the systematic experimental design involved catalytic copyrolysis by varying the operating parameters of the pyrolysis temperature (400-500 °C), the inert nitrogen flow rate (25-150 mL/min), and the ratio of blended ULO/UCO from 0.9:0.1 to 0.2:0.8. The advantage of Ni modified to activated carbon is that it is considered a stronger acid solid catalyst with an extraordinary pore structure, which undergoes catalytic copyrolysis; the concentration of the Ni metal doped into the AC catalyst was 3-10 wt %, and the catalyst loading on the feedstocks (5-20 wt % of Ni/AC catalyst) was performed. The effects of the conversion of ULO/UCO on the yield and physicochemical properties of copyrolysis oil and the product distribution according to ASTM D86 were investigated. The 5 wt % Ni doped into the AC catalyst is related to the strength of the acid activity that accelerated the conversion of large hydrocarbon compounds to obtain a straight aliphatic hydrocarbon compound, and the Ni/AC catalyst also plays a role in facilitated C-C bond cleavage and bond scission to smaller hydrocarbon compounds. The highest yield of naphtha-like fraction of 25.34 wt % was obtained at the optimal condition of 425 °C, the N2 carrier flow rate was 50 mL/min, the ULO/UCO ratio was 0.5:0.5, 5 wt % Ni was modified into the AC catalyst, and 5% catalyst was loaded into the feedstock. The synergistic effects of UCO and ULO during copyrolysis also revealed that the H-donor and hydrocarbon radicals of UCO decrease the thermal stability of ULO, whereas the addition of 5 wt % Ni to the AC catalyst, which is relevant to acid activity, is mainly responsible for bond scission, hydrogenation, isomerization, and oligomerization, resulting in the formulation of condensable volatile vapors to maximize the production of straight aliphatic and olefinic hydrocarbon compounds, which can be used as sustainable fuels from the conversion of waste to alternative energy.

Fatty acid wax from epoxidation and hydrolysis treatments of waste cooking oil: synthesis and properties

To provide low-cost wax and a new methodology for utilizing waste cooking oil (WCO), fatty acid wax based on WCO was synthesized by using epoxidation and hydrolysis treatments, whose properties included melting point, color, hardness, combustion properties, aldehyde content, and microscopic morphology were tested and analyzed. The obtained WCO-based wax contained mixed fatty acids, including palmitic acid and 9,10-dihydroxystearic acid as main constituents, which could form a 3D stable crossing network constructed by large long-rod crystals. The WCO-based wax with high fatty acid content (96.41 wt%) has a high melting point (44-53 °C), light color (Lovibond color code Y = 11.9, R = 2.3), good hardness (needle penetration index = 2.66 mm), long candle burning time (293 min), and low aldehyde content (7.98 × 10^-2 μg g^-1), which could be a lower-cost alternative of commercial soybean wax (SW) for producing various wax products including candles, crayons, waxworks, etc.

Enhanced production of amyrin in Yarrowia lipolytica using a combinatorial protein and metabolic engineering approach

BACKGROUND

Amyrin is an important triterpenoid and precursor to a wide range of cosmetic, pharmaceutical and nutraceutical products. In this study, we metabolically engineered the oleaginous yeast, Yarrowia lipolytica to produce α- and β-amyrin on simple sugar and waste cooking oil.

RESULTS

We first validated the in vivo enzymatic activity of a multi-functional amyrin synthase (CrMAS) from Catharanthus roseus, by expressing its codon-optimized gene in Y. lipolytica and assayed for amyrins. To increase yield, prevailing genes in the mevalonate pathway, namely HMG1, ERG20, ERG9 and ERG1, were overexpressed singly and in combination to direct flux towards amyrin biosynthesis. By means of a semi-rational protein engineering approach, we augmented the catalytic activity of CrMAS and attained ~ 10-folds higher production level on glucose. When applied together, protein engineering with enhanced precursor supplies resulted in more than 20-folds increase in total amyrins. We also investigated the effects of different fermentation conditions in flask cultures, including temperature, volumetric oxygen mass transfer coefficient and carbon source types. The optimized fermentation condition attained titers of at least 100 mg/L α-amyrin and 20 mg/L β-amyrin.

CONCLUSIONS

The design workflow demonstrated herein is simple and remarkably effective in amplifying triterpenoid biosynthesis in the yeast Y. lipolytica.