Rapid detection of meso-diaminopimelic acid in lactic acid bacteria by microwave cell wall hydrolysis

Two innovative microwave hydrolysis procedures for rapidly detecting meso-diaminopimelic acid in lactic acid bacteria have been developed. Whole-cell hydrolysis was performed both in liquid phase and vapor phase with 6 N HCl in sealed vessels using a microwave oven equipped with pressure and temperature probes. The presence or absence of meso-diaminopimelic acid determined by TLC, after the application of liquid- and vapor-phase microwave hydrolysis procedures, gave the same qualitative results as those obtained by traditional hydrolysis. These standardized microwave hydrolysis procedures permit a drastic reduction in hydrolysis time, from 16-20 h to less than 10 min and, consequently, in the total time of meso-diaminopimelic acid analysis (less than 90 min). Microwave hydrolysis in vapor phase is particularly convenient because, besides reducing hydrolysis time, it also eliminates the successive troublesome step of HCl removal.