Efficient biomass-endopolysaccharide production from an identified wild-Serbian Ganoderma applanatum strain BGS6Ap mycelium in a controlled submerged fermentation

Abstract

A rare wild-Serbian Ganoderma applanatum strain BGS6Ap (GASB) was morphologically identified based on its basidiocarp with brownish-red cap and woody stipe. Molecularly, GASB DNA was extracted, sequenced (651 bp) and subjected to phylogenetic analysis with evolutionary distance (Knuc). A plasmid Editor (ApE) software was used to verify the sequence and GASB was found to be 99% similarity to the commercial G. applanatum (GA) ATCC44053. The production of GASB's biomass and endopolysaccharide (ENS) in different temperature was screened at 20 °C, 25 °C and 30 °C via one-factor-at-a-time (OFAAT) scheme in a submerged liquid fermentation (SLF). Lower temperature was chosen due to GASB's natural habitat, which belongs to temperate continental climates with the influence of air currents from the Carpathians and the Mediterranean. Using the OFAAT data, the SLF was further optimised using response surface methodology (RSM) to generate biomass-ENS based on temperature (20°C–30 °C), agitation rate (100–200 rpm), glucose concentration (10 g/L–50 g/L) and initial pH (4–6). The highest production of biomass (17.51 g/L) and ENS (3.47 g/L) was generated using optimal conditions of 25 °C, 150 rpm, 10 g/L of glucose and pH 6. To study the structural composition, ENS confirmed spectral linkages in FTIR (2925 cm−1, 1623 cm−1, 1073 cm−1, 890 cm−1) and NMR (δ 4.30, 4.80, 5.20 ppm) as endo-β-D-glucan. This approach could serve as a blueprint for novel mycelial biomass and endo-β-D-glucan production of GASB which can be further studied on different temperate basidiomycetes.