Ondersoekinge oor die afbraak van aromatiese verbindings deur mikro-organismes

[摘要] English: 1. In a survey of the relevant literature the methods ofinvestigation, the systematic and biochemical aspects and thesignificance of microbial degradation of aromatic compounds has beendiscussed.2. In a preliminary investigation it was found that nonselectivilyisolated strains of streptomycetes dit not grow on amineral salt medium with a simple aromatic compound as sole sourceof carbon.3. Bacteria, fungi and one Nocardia strain able to use aromatic compounds as sole source of carbon and energy, were isolated from enrichment cultures.4. From turbidimetric growth measurements it was found thatoptimum cell development of the bacteria and actinomycete investigatedin a medium with a low concentration of aromatic substratein most cases took place within two days.5. The oxidation of a number of aromatic compounds by thebacteria and actinomycete isolated, was studied with the aid of thedirect method of Warburg.6. The method used for the calibration of manometers andWarburg flasks is described.7. The technique of sequential induction was applied todetermine the pathway of microbial degradation of the aromaticcompounds investigated. With this technique the following hithertounpublished reactions of bacteria have been found:(i) Salicylic acid - gentisic acid.(ii) Saligenin - salicylic aldehyde - salicylic acid - catecholand gentisic acid.(iii) Syringic acid - gallic acid.(iv) Guaiacol - catechol.(v) Vanillin - vanillic acid - protocatechuic acid.(vi) Veratric aldehyde - veratric acid - vanillic acid - protocatechuic acid.The degradation of phenol, benzoic acid, mandelic acid,p-cresol, m-hydroxybenzoic acid and anisic acid by bacteria, and oftoluene by Nocardia sp., as studied with manometrical methods, wasfound to be identical with the pathway already described for bacteriaand fungi. The degradation pathway of o- and m-cresol could not beestablished with certainty with the method used.

[发布机构] University of the Free State