Abstract
Orange bagasse comprising pulp tissues, rind, and seeds, constitutes a major industrial food waste arising from processing oranges for juice, and represents a fermentation feedstock for the production of enzymes. Botryosphaeria rhodina MAMB-05 grown on essential oils-extracted orange bagasse in submerged (SmF) and solid-state fermentation (SSF) with and without added nutrients produced pectinase and laccase. Highest enzyme titres (pectinase, 32 U ml-1; laccase, 46 U ml-1) occurred in SSF without added nutrients, indicating nutrient sufficiency of orange bagasse at a solids concentration of 16 % (w v-1) to sustain growth and high enzyme titres. Orange essential oil extract added to nutrient medium containing 1 % glucose in SmF strongly inhibited fungal growth with consequent lower laccase and pectinase activities. The results demonstrate the need to remove the essential oils fraction before citrus waste can be successfully used as a fermentation substrate for enzyme production.Download PDF