A novel Pseudomonas gessardii strain LZ-E simultaneously degrades naphthalene and reduces hexavalent chromium

Combined pollutants with polycyclic aromatic hydrocarbons (PAHs) and heavy metals have been identified as toxic and unmanageable contaminates. In this work, Pseudomonas gessardii strain LZ-E isolated from wastewater discharge site of a petrochemical company degrades naphthalene and reduces Cr(VI) simultaneously. 95% of 10 mg L−1 Cr(VI) was reduced to Cr(III) while 77% of 800 mg L−1 naphthalene was degraded when strain LZ-E was incubated in BH medium for 48 h. Furthermore, naphthalene promotes Cr(VI) reduction in strain LZ-E as catechol and phthalic acid produced in naphthalene degradation are able to reduce Cr(VI) abiotically. An aerated bioreactor system was setup to test strain LZ-E's remediation ability. Strain LZ-E continuously remediated naphthalene and Cr(VI) at rates of 15 mg L−1 h−1 and 0.20 mg L−1 h−1 of 800 mg L−1 naphthalene and 10 mg L−1 Cr(VI) addition with eight batches in 16 days. In summary, strain LZ-E is a potential applicant for combined pollution remediation.