Phenol Degradation Kinetics by Free and Immobilized Pseudomonas putida BCRC 14365 in Batch and Continuous-Flow Bioreactors

Abstract

Phenol degradation by Pseudomonas putida BCRC 14365 was investigated at 30 °C and a pH of 5.0–9.0 in the batch tests. Experimental results for both free and immobilized cells demonstrated that a maximum phenol degradation rate occurred at an initial pH of 7. The peak value of phenol degradation rates by the free and immobilized cells were 2.84 and 2.64 mg/L-h, respectively. Considering the culture at 20 °C, there was a lag period of approximately 44 h prior to the start of the phenol degradation for both free and immobilized cells. At the temperatures ranging from 25 to 40 °C, the immobilized cells had a higher rate of phenol degradation compared to the free cells. Moreover, the removal efficiencies of phenol degradation at the final stage were 59.3–92% and 87.5–92%, for the free and immobilized cells, respectively. The optimal temperature was 30 °C for free and immobilized cells. In the batch experiments with various initial phenol concentrations of 68.3–563.4 mg/L, the lag phase was practically negligible, and a logarithmic growth phase of a particular duration was observed from the beginning of the culture. The specific growth rate (μ) in the exponential growth phase was 0.085–0.192 h−1 at various initial phenol concentrations between 68.3 and 563.4 mg/L. Comparing experimental data with the Haldane kinetics, the biokinetic parameters, namely, maximum specific growth rate (μmax), the phenol half-saturation constant (Ks) and the phenol inhibition constant (KI), were determined to equal 0.31 h−1, 26.2 mg/L and 255.0 mg/L, respectively. The growth yield and decay coefficient of P. putida cells were 0.592 ± 4.995 × 10−3 mg cell/mg phenol and 5.70 × 10−2 ± 1.122 × 10−3 day−1, respectively. A completely mixed and continuous-flow bioreactor with immobilized cells was set up to conduct the verification of the kinetic model system. The removal efficiency for phenol in the continuous-flow bioreactor was approximately 97.7% at a steady-state condition. The experimental and simulated methodology used in this work can be applied, in the design of an immobilized cell process, by various industries for phenol-containing wastewater treatment.

Phenol Degradation by Pseudarthrobacter phenanthrenivorans Sphe3

“…Lower growth at 300 mg/L phenol could be explained by the growth-limiting factor of the substrate (carbon source) concentration, while the lower growth at phenol concentration above 1000 mg/L suggest the toxic effect of phenol on Sphe3 cells. A similar phenomenon of increasing growth and degradation efficiency with increasing the substrate concentration and then decreasing above a concentration threshold, indicating substrate inhibition kinetics has been reported by others [ 2 , 44 , 45 ].…”

“…Immobilized Bacillus sp. SAS19 exhibited lower degradation activity compared to free bacterial cells [ 52 ], while immobilized Pseudomonas putida BCRC 14365 showed a slightly lower degradation rate of phenol than the free cells [ 44 ]. Moreover, immobilized Acinetobacter sp.…”

2,4-Dichlorophenol biotransformation using immobilized marine halophilic Bacillus subtilis culture and laccase enzyme: application in wastewater treatment

“…Our findings are in agreement with Yordanova et al [33], who found that the degradation of phenol and 2,4-DCP by immobilized cultures was faster than 2-CP and 4-CP degradation. In addition, numerous reports demonstrated that the immobilized cultures process the highest removal potency for different CPs than free cultures [34][35][36].…”

“…The results of the present investigation also showed that the immobilized cultures and enzymes were relatively stable for a long time. The reused immobilized cultures and enzymes can be considered a crucial parameter in an industrial treatment, which determines the effectiveness of biotransformation over time [36]. Luffa pulp (as an adsorbed solid support) recorded lower cell leakage, maximum mechanical stability, and resistance to biological and chemical degradation, making it suitable for an extended period of repetition [43].…”

Enhanced degradation of phenol by a novel biomaterial through the immobilization of bacteria on cationic straw

“…Because of the advantages of complete degradation and no secondary pollution, biodegradation is widely regarded as a practical, economical and promising method (Azadi & Shojaei 2020;Lee et al 2020;Nogina et al 2020). Various kinds of microorganisms with the ability of degradation of phenol have been favored, such as Pseudomonas, Acinetobacter, Yeasts, and activated sludge with a wide variety of microorganisms (Filipowicz et al 2020;Lin & Cheng 2020;Liu et al 2020;He et al 2021). In general, as the increase of the concentration for hazardous pollutants, the ability of natural microorganisms for degradation is decreased.…”