Characterisation of Leuconostoc spp. isolates causing sugar cane juice quality deterioration in Kenya

Abstract

Sugar cane (Saccharum officinarum L.) is one of several perishable industrial crops that should be processed immediately after harvesting. In Kenya, harvested sugar cane takes 1-7 days before milling. Delay beyond this period causes the sugar cane to deteriorate due to the Leuconostoc mesenteroides bacteria, which invade the harvested sugar cane through the cut ends. The objective of this study was to isolate and characterise isolates of Leuconostoc spp. from sugar cane-growing regions in Kenya. The study was conducted on isolates sourced from three main sugar cane growing regions in Kenya, namely Kakamega, Nyando and South Nyanza (Sony sugar). Four sugar cane varieties, namely KEN 83-737, KEN 82-808, N14, and Co421 were used for this purpose. The isolates were identified by their morphological and biochemical characteristics. Deterioration parameters (brix% juice, pol% juice, dextran and pH) were evaluated over 10 days. The results revealed that Sony sugar isolate was responsible for the highest levels of sugarcane deterioration, whereas the Kakamega and Nyando isolates exhibited the lowest levels of deterioration. N14 and Co421 were the most and least degraded sugarcane varieties, losing 2195.38 and 1093.16 g of sucrose to dextran, respectively.