Complex sentence: Various microorganisms are involved in a two-stage process of degradation of PCBs, which happens in aerobic and anaerobic environments degradation of PCBs is similar to the degradation of biphenyl.
Split into simpler sentences: Various microorganisms are involved in a two-stage process of degradation of PCBs, which happens in aerobic and anaerobic environments. Degrading PCBs is similar to the degradation of biphenyl.