Biodegradation of penicillin G from industrial bacteria residue by immobilized cells of Paracoccus sp. KDSPL-02 through continuous expanded bed adsorption bioreactor

Abstract

Background: An efficient biodegradation-strengthening approach was developed to improve penicillin G degradation from industrial bacterial residue in an expanded bed adsorption bioreactor (EBAB) is reported in this paper.

Results: Paracoccus sp. strain KDSPL-02 was isolated based on its ability to use penicillin G as the sole carbon and nitrogen source. Strain identification was based on analyses of morphology, physio-biochemical characteristics, and 16S rDNA sequences. The effects of temperature, pH, PVA-sodium alginate concentration, calcium chloride concentration and initial penicillin G concentration were investigated. Repeated operations of immobilized cells with EBAB, At initial penicillin concentrations below 2.0 g L^{- 1}, the continuous mode could reach more than 20 times, and the degradation rate reached 100%.

Conclusions: The present study suggests that the EBAB system can be utilized for the simple and economical biodegradation of penicillin G from industrial bacterial residue.

Keywords: Expanded bed adsorption bioreactor; Immolilization; Paracoccus sp.; Penicillin G.

Fig. 1

Schematic dragram of the EBAB system used in penicillin G biodegradation

Fig. 2

Phylogenetic analysis of the strain KDSPL-02 related species by the neighbour-joining approach. The scale bars represent 0.005 substitutions per site

Fig. 3

The influence of temperature on the degradation activity of free and immobized KDSPL-02 cell. (black square refers free cells, red circle refers immobilized cells)

Fig. 4

Effect of pH on the degradation ability of the immobilized KDSPL-02. (black triangle refers free cells, red circle refers immobilized cells)

Fig. 5

Effect of support materials and cross-linking solution concentration on the formation of immobilized beads. a Effect of PVA concentration on the formation of immobilized beads (black square refers 2.0% PVA, red circle refers 2.5% PVA, blue up triangle refers 3.0% PVA, green down triangle refers 3.5% PVA, pink left triangle refers 4.0% PVA); b Effect of calcium chloride concentration on the formation of immobilized beads (black square refers 1.8% calcium chloride, red circle refers 2.0% calcium chloride, blue triangle refers 2.2% calcium chloride); c Effect of sodium alginate concentration on the formation of immobilized beads (black square refers 2.0% sodium alginate, red circle refers 2.5% sodium alginate, blue up triangle refers 3.0% sodium alginate, green down triangle refers 3.5% sodium alginate, pink left triangle refers 4.0% sodium alginate)

Fig. 6

Degradation of free and immobilized cells with different initial concentrations of Penicillin G. (black square refers 1.6 g/L immobilized cells, red circle refers 1.6 g/L free cells, blue up triangle refers 1.2 g/L immobilized cells, green down triangle refers 1.2 g/L free cells)

Fig. 7

Repeated batch Penicillin G biodegradation in EBAB system. Biodegradation conditions: 30 °C, pH 7.0, 3.0% sodium alginate, 3.0% PVA and 2.0% calcium chloride. Initial Penicillin G concentration was 1.2 g L⁻¹

Fig. 8

Penicillin G degradation activity of clear liquid and crude liquid in expanded bed reactor. (black square refers clear liquid, red circle refers crude liquid)