Our new range of chromogenic substrates are based on the core molecule 2,3-dihydroxynaphthalene (DHN, product code 80XXX). DHN-substrates are colourless; however, when cleaved in the presence of an iron salt they produce an intense, highly-visible, purple colour. The substrates are suitable for use in liquid or tube media under both aerobic and anaerobic conditions. They offer a number of advantage over other commonly used substrates, one major advantage being that the intense purple colour is able to mask the yellow produced by ONPG cleavage, making DHN-substrates especially suitable for dual chromogenic systems. 

The novel range of 6,7-Dibromo-2,3-Dihydroxynaphthalene (Brown, product code 56XXX) substrates for use in agar plates for the detection of Gram-negative organisms under both aerobic and anaerobic conditions. They offer easy detection of any enzyme-positive reaction by eye, when used with an iron salt in the growth medium, giving discreate red-brown coloured colonies on the plates.

DHN and Brown substrates are protected by European Patents EP3066107, EP3066209 and US Patents US9879303, US9938562, US10443084 if appropriate, as indicated under each product.