Characterization of best naringinase producing fungus isolated from the citrus fruits

Abstract

Naringinase enzyme has potential application in food and pharmaceutical industry. Naringin and limonin are principle bitter components in the citrus fruit. The microorganisms that associate with citrus fruit may have the ability to degrade the naringin by extracellular naringinase enzymes that are produced by microorganisms. The objective of the study is to isolate naringinase producing fungus from the citrus fruit to debitter the citrus juice and to characeterize the fungus. Citrus fruits were allowed to spoil under the air and soil and the lesion was used to streak on fresh PDA plates. Out of the eight strains isolated from citrus fruits, five were positive for naringinase enzyme. When all the naringinase producing fungi were subjected to liquid fermentation medium for eight days at room temperature at 200 rpm and the crude enzyme was tested for naringinase enzyme at pH 5 and 50 ºC for 10 minutes, one strain showed the best naringenase activity (1.92 µmol/ml/min). This strain was identified as Aspergillus flavus based on the macroscopic, microscopic and biochemical tests. The culture conditions were optimized to increase the naringinase production via solid state fermentation system using paddy husk as the support. Though naringinase activity of Aspergillus flavus has started on the 2nd day, the highest activity (449.58Ug -1 Dry Matter) was obtained on the 8th day. Thereafter the naringinase activity has started to decline. Solid state fermentation using paddy husk as support could be used for large scale naringinase enzyme production.

Microorganisms, the Ultimate Tool for Clean Label Foods?

“…The range of pH stability is generally from 4 to 8 [45,50,51]. In 2016, Srikantha et al [52] reached an activity as high as 449.58 U/g of dry matter in solid state fermentation for Aspergillus flavus. Some studies focused on the capacity of bacteria to produce naringinases, such as Bacillus spp.…”

Source, Production, Immobilization and Industrial Applications of Debittering Enzyme Naringinase: Review

“…Under the effect of optimized conditions, the loading capacity was found to increase by as high as 28 folds. In another study, Srikantha et al [18] utilized paddy husk and five different strains of fungi to screen their potential to produce the enzyme naringinase. The study reported that the strain Aspergillus flavus produced the maximum (highest) amount of enzyme among the compared strains of fungi.…”