Products Microbiological media ready to use Test tubes Hugh-Leifsson’s substrate, paraffin. PwP-0027 Hugh-Leifsson’s substrate, paraffin. PwP-0027 Categories Test tubes Product description Catalogue number: PwP-0027 Application: Substrate for detecting the aerobic or anaerobic breakdown of carbohydrates – glucose. Pack size: 40 test tubes x 3 ml