Mr Walker (36) will graduate from the university with a PhD in microbiology and immunology tomorrow.
His main supervisor is Otago University microbiologist Prof John Tagg, a New Zealand pioneer of the concept of using bacteriocin-like inhibitory substances (Blis), produced by naturally occurring oral bacteria, to counter bacterial pathogens in the human mouth and throat.
Mr Walker said some dental plaque was a ''glue-like gel'' that prevented the large Blis proteins from penetrating, somewhat limiting their effectiveness in attacking pathogens situated close to the tooth.
His research had investigated the possibility of launching a two-phase attack on plaque, first by using a naturally occurring enzyme, dextranase, to break into it.
Breaking up the plaque would then allow large Blis proteins to attack the oral pathogens, particularly mutans streptococci (MS) bacteria, that caused tooth decay.
There were promising early indications this approach could ''increase the killing efficacy of anti-MS bacteriocins'' in plaque.
''I feel very pleased that a lot of hard work paid off,'' he said this week.
Theoretically, a probiotic product could be developed to combine beneficial, naturally occurring bacteria that generated the enzyme, and other organisms that produced the pathogen-killing bacteriocin, to counter oral plaque.
''If a product went to market and people got benefit from it, that would be quite amazing,'' Mr Walker said.
''Dental caries is the most prevalent infectious disease of humans and can ultimately result in destruction of affected teeth,'' he said.
''Recent studies indicate that there is a resurgence of dental caries occurrence in both developing and developed countries.''
Prof Tagg said Mr Walker should be ''proud'' of his research, which highlighted a promising new line of attack on dental pathogens.
