Enhanced glucosamine production from Aspergillus oryzae NCH-42 via acidic stress under submerged fermentation

Abstract

Glucosamine (GlcN) has been widely used to treat osteoarthritis. However, GlcN derived from crustacean shells has several drawbacks, and it is not vegan-friendly. Here, we produced GlcN from the biomass of Aspergillus oryzae NCH-42 and investigated the effects of environmental factors (e.g. carbon and nitrogen sources, temperature, and pH) on the GlcN production of the fungal biomass. The acidic stress resulted in significantly higher GlcN content in the cell wall of A. oryzae NCH-42. Moreover, the SEM examination revealed that the mycelial structure grown at pH 2.5 was thick and sturdy, compared to that at neutral pH conditions. The final yield of GlcN could be enhanced by up to 7.75-fold by cultivating at modified PDB with an initial pH of 2.5 at 30°C for 4 days. In this study, the GlcN content of A. oryzae biomass could reach up to 0.31 g/g biomass, indicating its high potentiality for GlcN production. Aumento de la producción de glucosamina a partir de Aspergillus oryzae NCH-42 mediante estrés ácido en fermentación sumergidaLa glucosamina (GlcN) se ha utilizado ampliamente para tratar la artrosis. Sin embargo, aquella que deriva de los caparazones de crustáceos presenta varios inconvenientes y no es apta para veganos. En el presente estudio produjimos GlcN a partir de la biomasa de Aspergillus oryzae NCH-42 e investigamos los efectos de los factores ambientales (por ejemplo, las fuentes de carbono y nitrógeno, la temperatura y el pH) en la producción de GlcN de la biomasa fúngica. El estrés ácido dio lugar a un contenido de GlcN significativamente mayor en la pared celular de A. oryzae NCH-42. Además, el examen SEM permitió comprobar que la estructura micelial cultivada a pH 2.5 era gruesa y robusta, en comparación con la cultivada en condiciones de pH neutro. El rendimiento final de GlcN se pudo multiplicar hasta por 7.75 al cultivarla en PDB (caldo de dextrosa de papa [patata]) modificado con un pH inicial de 2.5 a 30°C durante 4 días. En este estudio, el contenido de GlcN de la biomasa de A. oryzae alcanzó hasta 0.31 g/g de biomasa, lo que indica su alta potencialidad para producir GlcN.

Strategies for the Enhancement of Secondary Metabolite Production via Biosynthesis Gene Cluster Regulation in Aspergillus oryzae

“…Therefore, manipulating the temperature and other environmental factors modulates the transcriptional expression of AoErg19 to regulate the biosynthesis of corresponding secondary metabolites. The yield of A. oryzae NCH-42 was low at 20 • C, while the yields of GlcN were high at 25 • C and 30 • C [93]. Additionally, a study using A. oryzae to produce fructo-oligosaccharides revealed that the enhanced activity of mutant V242E is not affected by reaction temperature or other environmental factors [107].…”

“…The pH also influences GlcN yield. At pH 2.5, A. oryzae NCH-42 produces the highest GlcN yield, with GlcN concentration and content being 4.1 and 2.4 times higher than those at pH 4~7, respectively [93]. However, excessive acidity (pH 2.0) significantly reduces the GlcN yield of A. oryzae NCH-42, making it inefficient under acidic conditions.…”

“…GlcN is an amino monosaccharide and structural component of chitin and chitosan, with diverse therapeutic effects such as antioxidation, anti-aging, and anti-inflammation [92]. Increasing the nitrogen sources significantly increases the GlcN concentration in A. oryzae NCH-42, with yeast extract being the optimal nitrogen source [93]. Yeast extract and NaNO 3 are also the optimal nitrogen sources for the production of anhydromevalonolactone (AMVL), a naturally occurring compound that can be heterogeneously expressed by A. oryzae MTG4 [94].…”