John Guest Phillips Travelling Scholarship
Report from Richard Meanwell
Department of Chemical Engineering, Loughborough University

The John Guest Phillips Travelling Scholarship allowed me to work for two weeks at UAM, Universidad Autónoma Metropolitana, in Mexico City, Mexico.

Part of my research examines the use of lactic acid bacteria (those bacteria which produce lactic acid during fermentation) to stabilise a chitinous waste material so that it can be used to produce antibiotics using another biological fermentation. This solid-state lactic acid fermentation of prawn/shrimp waste material was pioneered here at Loughborough, and a slightly different system is being used in UAM, Mexico.

During my stay, I had the opportunity to use their particular fermentation column, a vertical packed column; a much simpler system than the system used in Loughborough, which consists of a horizontal basket which rotates periodically to promote mixing of all the fermentation components. Work recently carried out in Mexico shows that their vertical packed column produces excellent results for lactic acid fermentation, and furthermore, that there appears to be no practical upper limit to the amount of time that waste can be fermented – contrary to the method used here at Loughborough, the waste never spoils. 

My particular brief piece of work consisted of adding a recycle system to the column. The initial fermentation mix consists of the prawn/shrimp waste, an inoculum (starter culture) of lactic acid bacteria, and sugar. During the fermentation, the sugar is converted to lactic acid by the bacteria, which preserves the material. However, liquid is produced as the fermentation progresses, into which the sugar can dissolve. As the liquid passes through the column and eventually to a space in bottom below the solid, the sugar contained there can no longer be fermented for use with the chitinous waste. It was found through my work that recycling this liquid increased the efficiency of this column system significantly – in fact, all the glucose was converted to lactic acid. 

Although this work was interesting in itself, the knowledge and skills I gained at UAM have allowed me to start to design a new reaction system for use with my particular research: a vertical rotating column system with liquid recycle. This combination of ideas from UAM and Loughborough should allow me to achieve the aim of my research – to combine two separate fermentations to produce antibiotics from a waste material.

Secretary to Prizes Committee
April 2002
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