A pyridine degradading bacterium was isolated from industrial wastewater and identified as a new Gram negative Pseudomonas sp. strain MG. This strain could degradate pyridine utilizing pyridine as a sole carbon, nitrogen and energy source. Usually pyridine containing wastewater was contaminated by other toxic compounds such as phenol and methylpyridines. When the bacterium was exposed to these secondary toxicants pyridine biodegradation activity was dramatically decreased and subsequently biodegradation of pyridine was impossible. So as a protection method from these secondary toxicants calcium alginate immobilization technique was used. With this technique pyridine degradation rate was guaranted safely and the protection technique against inhibition by secondary toxicants made pyridine biodegradation possible.