Characterization of a Multifunctional Monascus Isolate NTU 568 with High Azaphilone Pigments Production

Abstract

Red mold rice is aerobic fungal grown rice on which Monascus sp. has been grown. NTU 568 strain was isolated from red mold rice by our laboratory. In our previous study, strain NTU 568 showed several bioactive functions of reducing blood serum lipid, relaying an anti-fatigue response, decreasing amyloid β peptide accumulation, and possibly preventing obesity. This research focused on the identification of strain NTU 568. The aim of this paper is to understand the taxonomic position of strain NTU 568 among other important Monascus spp. The morphological observations, which include colonies size, ascospores size, and the partial sequences of ribosomal RNA genes-the internal transcribed spacer 1/2 (ITS1/2), 5.8S/18S ribosomal RNA gene, polyketide biosynthesis gene and β-tubulin gene, were applied to identify the strain NTU 568. Comparisons of partial nucleotide sequences, morphology, and azaphilone pigment contents with the strains from different species (Monascus purpureus, Monascus ruber, and Monascus pilosus) were performed. The DNA sequences data indicated that strain NTU 568 was similar to BCRC 31615 (Monascus purpureus) obtained from the Food Industry Research and Development Institute (FIRDI). The contents of monascin (7060.8 mg/kg) and ankaflavin (6836.2 mg/kg) of red mold dioscorea by strain NTU 568 were higher than Monascus-grown products by different strains. The morphological observations, DNA sequences data, and secondary metabolite contents indicated that strain NTU 568 and BCRC 31615 were the same species, belonging to Monascus purpureus.

Keywords:

• Monascus
• ribosomal RNA gene
• polymerase chain reaction (PCR)
• sequencing
• azaphone pigments

ACKNOWLEDGMENTS

We would like to thank chief Yao-Haur Kuo for isolations and structural elucidation of azaphilone pigments from Monascus-fermented products in this study.