Effective decolorization of anthraquinone dye reactive blue 19 using immobilized Bacillus sp. JF4 isolated by resuscitation-promoting factor strategy.

Given the highly complex recalcitrant nature of synthetic dyes, biological treatment of textile wastewater using efficient bacterial species is still considered as an environmentally friendly manner. In this study, a reactive blue 19 (RB19)-degrading strain, Bacillus sp. JF4, which was isolated by resuscitation-promoting factor (Rpf) strategy, was immobilized into polyvinyl alcohol-calcium alginate-activated carbon beads (JF4-immobilized beads) for RB19 decolorization. Results suggest that the JF4-immobilized beads, which were capable of simultaneous adsorption and biodegradation, showed a high decolorization activity, while they exhibited better tolerability towards high RB19 concentrations. The JF4-immobilized beads could almost completely decolorize 100 mg/L RB19 within 10 d, while only 92.1% was decolorized by free bacteria within 12 d. Further investigation on the equilibrium and kinetics of the adsorption process suggests that the pseudo-second-order model best fit the adsorption kinetics data, and the Freundlich isotherm was the most suitable for the description of the equilibrium data. Notably, the repeated batch cycles indicated that complete decolorization of 100 mg/L RB19 by JF4-immobilized beads can be maintained for at least three cycles without much reduction in efficiency. These findings suggest that immobilizing Rpf-resuscitated strain into beads was an effective strategy for textile wastewater treatment.

A novel strategy for enhancing anaerobic biodegradation of an anthraquinone dye reactive blue 19 with resuscitation-promoting factors.

Anaerobic process has been widely applied as a cost-effective method for textile wastewater treatment. However, many bacteria exhibit low metabolic activity in unfavorable conditions due to the entry into a viable but non-culturable (VBNC) state. Thus, in this study, a novel method of using resuscitation-promoting factors (Rpfs), which has been proven to resuscitate and stimulate the growth of VBNC bacteria, is explored to enhance the degradation of the anthraquinone dye reactive blue 19 (RB19) in the anaerobic process. The results show that Rpfs could efficiently prompt RB19 decolorization. Compared to the conventional anaerobic condition, RB19 decolorization efficiency was increased by more than 20% with the Rpf addition. UV-visible spectral and gas chromatograph-mass spectrometry analysis indicate that the aromatic amines structures of RB19 was cleaved. More importantly, the Rpf addition appeared to stimulate and/or enrich some dye-degrading species of the family Peptostreptococcaceae, thus leading to a higher RB19 decolorization efficiency.

Resuscitation, isolation and immobilization of bacterial species for efficient textile wastewater treatment: A critical review and update.

Given highly complex and recalcitrant nature of synthetic dyes, textile wastewater poses a serious challenge on surrounding environments. Until now, biological treatment of textile wastewater using efficient bacterial species is still considered as an environmentally friendly and cost-effective approach. The advances in resuscitating viable but non-culturable (VBNC) bacteria via signaling compounds such as resuscitation-promoting factors (Rpfs) and quorum sensing (QS) autoinducers, provide a vast majority of potent microbial resources for biological wastewater treatment. So far, textile wastewater treatment from resuscitating and isolating VBNC state bacteria has not been critically reviewed. Thus, this review aims to provide a comprehensive picture of resuscitation, isolation and application of bacterial species with this new strategy, while the recent advances in synthetic dye decolorization were also elaborated together with the mechanisms involved. Discussion was further extended to immobilization methods to tackle its application. We concluded that the resuscitation of VBNC bacteria via signaling compounds, together with biochar-based immobilization technologies, may lead to an appealing biological treatment of textile wastewater. However, further development and optimization of the integrated process are still required for their wide applications.

Aerobic degradation of 3,3',4,4'-tetrachlorobiphenyl by a resuscitated strain Castellaniella sp. SPC4: Kinetics model and pathway for biodegradation.

Resuscitated strains which were obtained by addition of resuscitation promoting factor (Rpf) could provide a vast majority of microbial source for obtaining highly efficient polychlorinated biphenyl (PCB)-degrading bacteria. In this study, the Castellaniella sp. strain SPC4 which was resuscitated by Rpf addition showed the highest efficiency in degradation of 3,3',4,4'-tetrachlorobiphenyl (PCB 77) among the resuscitated and non-resuscitated isolates. Further investigations on the PCB 77 degradation capability of the resuscitated strain SPC4 showed that SPC4 could efficiently degrade PCB 77 with maximum degradation rate (qmax) of 0.066/h at about 20 mg/L of PCB 77. The maximum growth rate on PCB 77 was 2.663 × 107 CFU/(mL·h) (0.024/h). The most suitable model of Edward demonstrated that the SPC4 could achieve qmax of 0.9315/h, with substrate-affinity of 11.33 mg/L and substrate-inhibition constants of 11.41 mg/L. Meanwhile, the presence of bphA gene expression and chlorine ions release, together with the identification of metabolites, confirmed that the bph-encoded biphenyl pathway was involved in PCB 77 mineralization by SPC4. This report is the first to demonstrate aerobic degradation of PCB 77 by the resuscitated strain Castellaniella sp. SPC4, indicating excellent potential for PCB bioremediation.