Biodegradation of partially hydrolyzed polyacrylamide by immobilized bacteria isolated from HPAM-containing wastewater

The special function bacteria R2 was screened from hydrolyzed polyacrylamide (HPAM)-containing wastewater that could use HPAM as the sole carbon source and nitrogen source. Through optimizing the condition of HPAM biodegradation, the removal rate of R2 free strain reached to 41.6% when pH was 7, temperature was 35 degrees C, inoculation quantity (v/v) was 3% and activation time was 4. In order to overcome the defects of bacteria loss and low microbial utilization rate, microbial immobilization was carried out by mixed bacteria embedding immobilized method. The removal efficiencies of HPAM and TOC were 79.4% and 80.39%, respectively. The immobilized beads was immobilized by embedding medium contained polyvinyl alcohol (PVA) and sodium alginate with concentration of 9% and 3% (w/v), respectively, and the volume ratio of wet bacteria and embedding medium was 1:1 with chemical cross-linked in the saturated boric acid solution. The strain R2 was identified as Pseudomonas aeruginosa UCBPP-PA14 through tests of physiological-biochemical characterization and 16S rDNA sequence. The SEM and HPLC analyses revealed that polyacrylamide was degraded into smaller molecular organism and there was no acrylamide monomer exists after biodegradation. It also could be observed from FT-IR and UV spectrograms that amide group was transformed into carboxyl group completely. (c) 2016 American Institute of Chemical Engineers Environ Prog, 35: 1344-1352, 2016