Problems of identifying phenolic compounds during the microbial degradation of olive mill wastewater

The main objectives of the presented Spanish-German collaboration are the purification of alpechin by biodegrading phenolic compounds and the investigation of metabolites during fermentation prior to its safe disposal. In addition to 12 well-known compounds, 3,4-dihydroxyphenylglycol was also identified in untreated Spanish and Italian alpechin samples using a GC/MS method. The qualitative composition of the Italian and Spanish samples differ. First results of degradation tests of reference substances are reported: Arthrobacter is capable of completely transforming added tyrosol to the corresponding 4-hydroxyphenylacetic acid and after 139h of fermentation no traces of tyrosol can be identified. In contrast, only traces of phenylacetic acid are produced by Bacillus pumilus after 139h of fermentation of tyrosol.