SPRI 2006 - SUGAR PROCESSING CONFERENCE

The Dr. Margaret A. Clarke Award

for

Best Paper

The Dr. Margaret A. Clarke Award for Best Paper presented at the International SPRI Conference on Sugar Processing Research, was presented by Mr. Robert O. Hatch, Chairman of SPRI to Dr. Gillian Eggleston, Lead Scientist, representing USDA-ARS-SRRC, New Orleans, Louisiana, USA, at the Grande Hotel São Pedro, in Águas de São Pedro, Brazil, on September 19, 2006.

SPRI wishes to thank Dr. Gillian Eggleston and co-authors, Dr. Henrique Amorim and S.C. de Lima Paulillo with Fermentec Ltda, Brazil, Dr. Luis C. Basso, and Tiago O. Basso, with the Universidade de São Paulo, Brazil, for their remarkable work presented at this year SPRI Conference on Sugar Processing Research with the theme “Frontiers in Sugar Processing Research,” in Águas de São Pedro, Brazil.  As the sugar industry moves forward with new processing and diversifying sugar research in sugarcane, sugarbeet and ethanol production we were pleased to congratulate Dr. Gillian Eggleston and co-authors in their interest and dedication as frontiers in a new age of sugar processing.  Abstract of paper presented is listed below.

ABSTRACT OF THE BEST PAPER PRESENTED

Mannitol as a Sensitive Indicator of Sugarcane Deterioration and Bacterial Contamination in Fuel Alcohol Production, Gillian Eggleston¹, L. C. Basso², H. Amorim³, S. C De Lima Paulillo³ and T. O. Basso^{2  1} USDA-ARS-SRRC, c/o Agronomy Dept., Louisiana State Univ., Baton Rouge, LA, USA. ²Universidade de São Paulo , Piracicaba , São Paulo , Brazil , ³Fermentec, Piracicaba , São Paulo , Brazil

Mannitol, formed mainly by Leuconostoc mesenteroides bacteria, is a very sensitive indicator of sugarcane deterioration that can predict processing problems. A rapid (4 to 7 min) enzymatic method has been developed to measure mannitol in juice pressed from consignments of sugarcane delivered to the factory. This screening tool will allow factory staff to rapidly know which consignments of cane will affect processing negatively or reject consignments that will cause unacceptable processing problems. This method can be easily performed using existing equipment in sugarcane factories, with mannitol being measured spectrophotometrically using mannitol dehydrogenase as the enzyme catalyst. The stability of the reagents, limited cane juice preparation, linearity, accuracy and precision are described. The method is highly specific for mannitol and was not affected by the presence of sucrose, glucose, fructose, or dextran. The current cost is only ~60 U.S. cents per analysis. Mannitol has also been proven to be an advantageous indicator of bacterial contamination - one of the main factors causing drops in fuel alcohol fermentation yields as well as yeast (Saccharomyces) flocculation and foaming problems. Compared to other indicators, mannitol is not produced by yeast cells, only contaminating bacteria (mostly some Lactobacillus strains) during fermentation; its concentration is directly associated with bacterial activity, and it can be measured easily. A strong correlation existed between mannitol formation and bacteria counts in sugarcane juice and molasses fermentations with induced bacterial contaminations.