Optical Microscopy Images Showing Enzymes (IMAGE) University of Bristol Caption Optical microscopy images showing a mixture of the liquid enzyme (yellow material) with the solid substrate (black crystals) immediately after contact (left), and after incubation for 30 min at 50°C (right). The development of the yellow colouration arises from the lipase-catalysed formation the yellow product. Credit University of Bristol Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.