Phenol biodegradation by two xenobiotics tolerant bacteria immobilized in polyethylene oxide cryogels

Biofilms were formed on poly(ethylene oxide) (PEO) cryogels by using bacteria cultured from xenobiotics polluted environments in order to investigate their phenol biodegradation capability. PEO cryogels were synthesized via UV irradiation cross linking of moderately frozen aqueous system. Two xenobiotics tolerant bacterial isolates KCM R5 and KCM RG5 were used to construct the biofilms on the surfaces of the cryogels. Obtained PEO-biofilms were assessed for their ability to remove phenol at concentrations – 300, 400, 600 and 1 000 mg L-1 for 28 days. The biofilm PEO-KCM RG5 removed phenol up to 600 mg L-1/24h, whereas the biofilm PEO-KCM R5 was able to degrade up to 1 000 mg L-1/24h. The high content of free-water in the cryogels allowed reproduction of the used bacteria. Short initial adaptation of the PEO-biofilms with 100 mg L-1/24h phenol was crucial for protecting the bacterial cells forming the biofilm from dead. The obtained results showed that the liquid debit through the biofilms at the 28-th day was lower if compared to the initial one. Cryogels demonstrated non-toxicity, high biocompatibility with bacteria and excellent mechanical characteristics. After the aggressive phenol treatment the PEO-biofilms remained compact, porous and elastic. The investigated new biological materials demonstrate potential for application in the industrial wastewater treatment technologies.