Comparison of 2-acetyl-1-pyrroline production between Aspergillus awamori and Aspergillus oryzae

Abstract

2-Acetyl-1-pyrroline (ACPY) is a key flavor compound in fragrant rice and widely exploited in food flavoring. It is produced by various microorganisms. This study focused on ACPY production by two fungi (Aspergillus awamori and A. oryzae). The volatile compounds derived from mold cultivation in synthetic medium 18 were identified by Gas chromatograph-mass spectrometer (GC-MS). Seven volatile substances were detected in the liquid culture of A. awamori, i.e. ACPY, one ketone (1-hydroxy-2-propanone), two acids (acetic acid and 4-hydroxybutanoic acid), two alcohols (2,3-butanediol and 2,5-dimethyl-4-hydroxy-3(2H)-furanone) and one saponin glycoside (2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one). Further, 12 volatile compounds were detected in A. oryzae : ACPY, four fatty acids (tetradecanoic acid, n-hexadecanoic acid, octadecanoic acid and oleic acid), one alcohol (1-butanol), two benzenes (ethylbenzene and benzene, 1,3-bis(1,1-dimethylethyl)), three alkanes (pentadecane, heptadecane and 5-methoxy-2,2,6-trimethyl-1-(3-methyl-buta-1,3-dienyl)-7-oxabicyclo[4.1.0] heptane) and one sesquiterpenes (1,6-dimethyl-4-(1-methylethyl)-naphthalene). Both A. awamori and A. oryzae produced the highest amount of ACPY in the stationary phase when cultivated for 72 and 80 h, with the product yield of 0.914 and 1.323 mg/L, respectively. The supplementation with spermidine and spermine resulted in a more than fivefold increase in ACPY production by A. awamori. However, the production of ACPY by A. oryzae was lower when supplemented with spermine or spermidine than without spermine or spermidine. This indicated that the intermediates involved in ACPY production were different between these two species of fungi.

Effect of polyamine on growth, intermediates and 2‐acetyl‐1‐pyrroline formation by Aspergillus awamori

“…According to a previous report, in the original Syn 18 medium with putrescine (2 g/L) as the N‐source, A awamori utilized the putrescine for growth at the first 36 h and later as the precursor of 2AP 24 . Therefore, inorganic nitrogen (2 g/L) was substituted in this study to see whether using more economic N‐source for primary growth would affect the 2AP production.…”

“…Five mL of spore suspension (2 × 10 9 spores/L) was transferred into 200 mL of potato dextrose broth and incubated in a shake flask (LabTech, Korea) (200 rpm) at 28 ºC for 3 days. The mycelia in the liquid medium were mixed using a sterile blender and were used as a starter culture 24 …”

“…The oven temperature was operated at 40 ºC for 1 min and then programmed from 40 ºC to 120 ºC at a rate of 9 ºC/min, and from 120 ºC to 230 ºC at a rate of 5 ºC/min. The carrier gas was helium, at a flow rate of 1.1 mL/min 7,24 . The amount of 2AP was calculated as mg/L of culture liquid.…”

“…The results showed that 2AP was formed as a secondary metabolite and the differences between those two species occurred when polyamine was added after 24 h of the incubation. The amount of 2AP was significantly higher in A awamori , in opposite to A oryzae , where the polyamine suppressed the production of 2AP 24 . Therefore, it is of interest to investigate how such polyamine influences 2AP production and growth in A awamori .…”

GC-MS and HPLC Analysis of Chlorophytum Borivilianum (Safed Musli) A Plant from Ayurveda- Herbal Viagra

“…The results of the present study are tabulated in Table 1. The identified constituents from the root extract of C. borivilianum like a saponin glycoside 4H-Pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl possess antifungal activity [13,14]…”