Remarkable improvement of levansucrase production from a newly isolated Aspergillus niger MK788296 strain using agro-industrial wastes through statistical optimization techniques

Abstract

Background and objective Microbial levansucrase (LS) is a good source for the production of biologically active fructo-oligosaccharides and levan, which have diverse applications in pharmaceutical industries. Therefore, recent studies have focused on the enhancement of LS production through searching for potent microbial producers and optimization of the fermentation conditions. The present study aimed to use agro-industrial waste as a cost-effective carbon source for LS production and maximize the enzyme yield by optimization of the cultural conditions. Materials and methods A potent fungal producer of LS was isolated from an Egyptian soil sample that was collected from Giza Governorate at a depth of 5 cm and identified based on internal transcribed spacer identification and then submitted to the gene bank database. The production of LS by the isolated strain was optimized by evaluating the best fermentation state and agro-industrial waste to be used in the fermentation process. After that, further optimization of culture medium composition was established by two statistical designs: the Plackett–Burman design followed by central composite design. Results and conclusion The isolated strain was identified as Aspergillus niger MK788296. The first optimization approach declared that using the submerged fermentation technique and utilizing potato peels as the main carbon source led to a 2.4-fold increase in LS production. The statistical optimization resulted in a massive LS production (18870.3 U/ml) with a 59.4-fold increase in enzyme yield than the nonoptimized culture conditions.