Comparison of mixed cultures based on activity

Biodegradation experiments using mixed bacterial cultures are difficult to compare because repeatable rates may not be produced in different experiments when cultures are normalized on a cell mass or number basis. A technique was therefore developed to quantify [¹⁴C]substrate-specific biodegradation activity of mixed cultures. The technique can be used to obtain a preliminary estimate of the substrate-degrading activity of a culture for more substantial experiments. The technique is applied to 1-naphthol-humic acid bioavailability experiments using both mixed and pure cultures to help isolate the impact of humic acid from differences between the cultures.