A rapid evaluation plate-test for the biodegradability of plastics

• Published in: Applied microbiology and biotechnology 1993-07, Vol.39 (4-5), p.673-678
• Main Authors: AUGUSTA, J, MÜLLER, R.-J, WIDDECKE, H
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biotechnology; Environment and pollution; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Miscellaneous
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/bf00205073

Solid-media agar-plate tests were investigated for their potential to evaluate the biodegradation of polymeric particles by certain strains of microorganisms. A reliable test was developed. Stable suspensions of 1- mu m globules of two poly(3-hydroxyalkanoates) were prepared. These were mixed with liquified agar-agar to form turbid plates. Inoculation was carried out by plate puncturing. Seven strains isolated from sewage sludge formed clear zones. These zones were distinct, circular, and reproducible in outlook and growth. The maximal duration of single experiments was 192 h. A growth rate was defined. It allowed the classification of the polymers, and of the microorganisms used. Poly(3-hydroxybutyrate-co-valerate) was degraded faster by all the strains used than was the homopolyester poly(3-hydroxybutyrate). Strains achieving high zone growth rates generally did so on both of the polymers. This led to the assumption of similar enzymatic processes being active. Zone formation was concluded to be dependent on the amount of enzyme production plus the enzyme activity. The technique provides a means of either distinguishing the degradation abilities of a microorganism, or the degradability of materials.