Immobilized CotA Laccase for Efficient Recovery of HEAVY OIL

CotA laccase was successfully expressed from Pichia pastoris . Magnetic reduced graphene oxide (MRGO) nanocomposite was synthesized and functionalized with iminodiacetic acid (IDA-NH 2 ), and then chelated with Cu 2+ for effective immobilization with His-tagged CotA laccase. The Cu 2+ -chelated MRGO (MRGO-IDA-Cu 2+ ) showed 175 mg/g-support adsorption capacity. The immobilization of CotA laccase with MRGO-IDA-Cu 2+ nano-hybrid composite was confirmed by Raman spectroscopy, Thermal Gravimetric Analysis, and X-ray diffraction. The use of nano-hybrid MRGO-IDA-Cu 2+ composite to improve heavy oil recovery was investigated. The findings revealed that the interfacial tension between oil and water was reduced to ~ 90% of its original value, and the wettability was changed from the oil-wet state [θ = ∼ 115.2 − 124.5°] to the water-wet state [θ = ∼ 8.9 − 30.1°]. The increase of immobilized CotA laccase concentration and the ratio of nano-hybrid MRGO-IDA-Cu 2+ composite decreases the value of interfacial tension (IFT) and contact angle (CA). The core-flooding studies revealed that the oil recovery process of 0.3 wt% nano-hybrid MRGO-IDA-Cu 2+ composite was enhanced by 82.8%. Graphical Abstract