DEXTRANASE FOR PROCESS EFFICIENCY IMPROVEMENT: THE THAI EXPERIENCE

Abstract

Sugarcane production in Thailand for the last milling season (2011–12) was around 98 million tonnes. Most of the cane had to be burnt before harvesting due to a shortage of manpower. The cut-to-crush time lasted more than 48 hours which resulted in the proliferation of micro-organisms, particularly Leuconostoc mesenteroides. The dextran product of the micro-organisms accumulated in the process and caused a lot of problems during the last milling period. Trials using dextranase were conducted at two sugar factories with capacities of 15 000 and 20 000 tonnes cane per day. The average concentrations of dextran in raw syrup and final molasses during observation were found to be around 1600 ppm and 2500 ppm, respectively. The enzyme was applied in the range of 2 to 5 ppm to the syrup before entering the last evaporator where the temperature was 65 to 70°C. The concentration of dextran in the final molasses was found to be 81% lower compared with no addition of enzyme. The recovery calculated as sugar of 96 pol was found to cover the enzyme cost during treatment.