Growth media are known to significantly influence secondary metabolite (SM) production with there being a continuing search for cheaper alternatives. Agro-residues constitute potential nutrient sources for growth and metabolite production by different microorganisms. Present study evaluated the potential of rice bran, wheat bran, soyabean chunks and potato peel for umbelliferone (UMB) production by endophytic fungal isolate ZzEF8 (Fusarium oxysporum) and compared the data with earlier optimized potato dextrose broth (PDB) medium. Biochemical studies identified higher reducing sugar (975±15 mg/ 100 ml) and total carbohydrate content (870±1.3 mg/ 100 ml) in PDB compared to the evaluated agroresidues. These results were supported by higher growth (Fresh weight: 2.08 ± 0.49 g and Dry weight: 0.214 ± 0.06 g) and metabolite production by ZzEF8 mycelia in PDB compared to the other evaluated agro-residue based media. Therefore, despite the environmental benefits associated with use of agroresidues, cost-intensiveness in downstream steps and low SM productivity often pose limitations to their utilization for several microbes. PDB as optimal media for growth and UMB production by endophytic ZzEF8 are discussed in the light of observed variability in composition of agro-residues.

Highlights

• Agro-residues showed low and variable umbelliferone (UMB) production by endophytic Fusarium oxysporum, ZzEF8 despite being sustainable alternatives.
• Maximum growth and UMB production by ZzEF8 were achieved in potato dextrose broth (PDB) due to its high nutrient content.
• Low nutrient content and variability in agro-residue media limit their effectiveness for metabolite production.