A New Approach of Rpf Addition to Explore Bacterial Consortium for Enhanced Phenol Degradation Under High Salinity Conditions

Abstract

Only a small fraction of salt-tolerant phenol-degrading bacteria can be isolated by conventional plate separation methods, because most bacteria in nature are in a viable but non-culturable (VBNC) state. The aims of this study were to screen out more effective functional bacteria using resuscitation-promoting factor (Rpf), and to determine whether a mixed bacterial consortium possesses better phenol-degrading capabilities under high salinity conditions. The results indicated that three strains unique to treatment group with Rpf addition were obtained. A mixed bacterial consortium consisting of two high-efficient strains which belonged to genera Bacillus and Corynebacterium was capable of utilizing phenol as a sole source of carbon at high salinity. Complete degradation of 100 mg/L phenol at 2% NaCl concentration was achieved within 8 h. This study provides new insights into resuscitation of VBNC bacteria for enhanced treatment of phenol-laden saline wastewater.

Intensification of Ex Situ Bioremediation of Soils Polluted with Used Lubricant Oils: A Comparison of Biostimulation and Bioaugmentation with a Special Focus on the Type and Size of the Inoculum

“…These findings not only indicate that a successful bioaugmentation treatment is strongly dependent on the degrader strain to be applied and its inoculum size, but further corroborates the idea that after a certain level of inoculation, an increased number of degrader cells used for bioaugmentation does not necessarily result in an enhanced bioconversion of soil pollutants. This phenomenon was previously reported only in aqueous systems [80,81]. According to the best of our knowledge, this study represents the first attempt to examine the effects of inoculum size on the bioaugmentation treatment of a long term ULO-contaminated soil.…”

Induction and Resuscitation of the Viable but Non-culturable (VBNC) State in Acidovorax citrulli, the Causal Agent of Bacterial Fruit Blotch of Cucurbitaceous Crops

“…The resuscitation promoting factor (Rpf), a small protein secreted by Micrococcus luteus in the late logarithmic phase of growth, plays an important role in the resuscitation and growth of dormant cells (Mukamolova et al, 1998, 2002; Li et al, 2018). The Rpf protein is widespread amongst bacteria, and has been detected in the supernatants of gram-positive and gram-negative bacterial cultures (Mukamolova et al, 2002; Li et al, 2014, 2018; Ramamurthy et al, 2014). In the public database (NCBI), there are 103 bacterial genes described as “resuscitation promoting factor” ( rpf ).…”

Challenges of unculturable bacteria: environmental perspectives

“…Nearly 1500 mg L -1 of phenol was degraded within 100 h in phenol-laden saline wastewater probably due to the resuscitation and stimulation of gammaproteobacterial and alphaproteobacterial populations (Su et al 2019b). In a search for further halotolerant phenoldegrader bacteria, several strains were isolated from a sewage treatment tank (Li et al 2018) and activated sludge samples (Su et al 2019b) by Rpf. Neutralization of phenolic wastewaters by applying Bacillus sp.…”

“…SAS19, either in a mixed consortium with Corynebacterium sp. SAS21 (Li et al 2018) or immobilized in porous gels (Ke et al 2018), represented the first application of a previously VBNC bacterium. Castellaniella sp.…”