Scaling-Up of a Lipase Fermentation Process: A Practical Approach

Abstract

LIPOMAX^TM, a lipase for application in heavy duty detergents (HDD) and light duty detergents (LDD), obtained by a new Pseudomonas alcaligenes technology, will be introduced in 1995 by Gist Brocades BV. A newly developed fermentation process for the production of LIPOMAX^TM was scaled up from 10 1 to an existing 100 m³ fermenter. A loss of production during scaling up was observed At 100 m³ scale, the maximum lipase concentration was reduced by 65% of the value at 101 scale. The following most likely possible causes, with the highest priority for investigation, were put forward: a) gradients of soy-oil, pH and oxygen, b) raw materials, medium preparation, sterilization procedure and inoculation procedure, c) dissolved carbon dioxide concentration, d) shear and air-broth interfaces. To study the above items at lab and 100 l scale, practical downscaling experiments were designed Medium and inoculum prepared at large scale was tested at lab scale. CO₂ was added to fermentations. Mixing effects were scaled down: pH, substrate and oxygen gradients were simulated at lab scale. Broth was subjected to high shear and large air-broth interfaces. Dissolved CO₂ was identified as the main cause for the scaling-up problem. An increased ventilation rate and a decreased head pressure combined with a lower pH, increased lipase production at 100 m³ up to values comparable to 10 l scale.