• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.830-834
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• 2003

The optimal condition for the production and extraction of monacolin K was reported. HPLC was used to determine monacolin K a kind of metabolite of Monascus from red-koji made of Monascus purpureus CBS 281.34. After culturing Monascus in solid and liquid media at $30^{\circ}C$ for 10 days, each of these were inoculated with soybean, wheat, barley, waxy rice, and rice and cultivated at $30^{\circ}C$ for 11 days. The production of monacolin K was the highest(0.35g/100g) when cultured with rice. The yield of monacolin K in red-koji increased with drying temperature and time according to the removal of water. Considering monacolin K content and the degree of death of Monascus, red-koji was dried at $80^{\circ}C$ for 60 min. Although monacolin K in red-koji was mostly extracted by 80% ethanol, there was no difference in monacolin K between shaking for 1 min and extraction for $0{\sim}24$ hr after sonication for 7 min. The extracted yield of monacolin K was the highest when the ratio of red-koji and 80% ethanol was 1:9. Moreover, the production of monacolin K appeared to be parallel with that of the pigment.

• KSBB Journal
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• v.23 no.6
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• pp.519-524
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• 2008

Monacolin-K is a strong anti-hypercholesterolemic agent produced by Monascus sp. via polyketide pathway. High-yielding mutants of monacolin-K were developed through rational screening strategies adopted based on understanding of monacolin-K biosynthetic pathway. Through the experiments for investigating various amino acids as putative precursors for the monacolin-K biosynthesis, it was found that production level of monacolin-K was remarkably increased when optimum amount of cysteine was supplemented into the production medium. We suggested that these phenomena might be related to the special roles of SAM (S-adenosyl methionine), a putative methyl group donor in the biosynthetic pathway of monacolin-K, demonstrating close interrelationship between SAM-synthesizing primary metabolism and monacolin-K synthesizing secondary metabolism. Namely, increase in the intracellular amount of SAM derived from the putative precursor, cysteine which was extracellularly supplemented into the production medium might contribute to the significant enhancement in the monacolin-K biosynthetic capability of the highly mutated producers. On the basis of these assumptions derived from the above fermentation results, we decided to construct efficient expression vectors harboring SAM synthetase gene (metK) cloned from A. nidulans, with the hope that increased intracellular level of SAM could lead to further enhancement in the monacolin-K production through overcoming a rate-limiting step associated with monacolin-K biosynthesis. Hence, in order to overcome the plausible rate-limiting step associated with monacolin-K biosynthesis by increasing intracellular level of SAM, we transformed the producer mutants with an efficient expression vector harboring gpdA promoter of the producer microorganism, and metK gene. Notably, from the resulting various transformants, we were able to screen a very high-yielding transformant which showed approximately 3.3 fold higher monacolin-K productivity than the parallel nontransformed mutants in shake flask cultures performed under the identical fermentation conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.164-169
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• 2004

We had screened the Monascus strain capable of producing monacolin K dominantly among 29 Monascus strains. Red yeast rice was prepared by culturing each Monascus sp. with 200 g of steamed rice (12$0^{\circ}C$, 20 min) at 3$0^{\circ}C$ for 10 days and drying at 8$0^{\circ}C$ for 20 min. As a result, red yeast rice cultured by M. purpureus ATCC16457, M. purpureu IFO 32316, M. purpureus IFO 32228, M. kaoliang ATCC 46595 and M. kaoliang ATCC 46596 produced lots of red pigment and monacolin K. An unidentified Monascus sp. showed the highest productivityof red pigment and monacolin K among 29 Monascus strains. Its production of red pigment and monacolin K was 1.3∼39 times and 2.4∼8 times higher than other strains, respectively. Although the morphological characteristics of unidentified Monascus strain were a little different from the typical M. purpureus, it was identified as M. purpureus CBS 281.34 from the result of sequencing of ITS (Internal transcribed spacer) and 28S ribosomal RNA (partial).

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.1022-1027
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• 2004

The monacolin K content was determined to investigate the stability of monacolin K from red yeast rice after heating (20∼8$0^{\circ}C$), adjusting the pH (2∼8) by adding 3 N HCl or 3 N NaOH, adding the organic acid (6.0% acetic acid, 0.6% citric acid, 1.5% lactic acid) to pH 4.0 and adding the water (0∼80%). And the monacolin K was isolated from red yeast rice by conducting open column chromatography using neutral aluminum oxide. As a result, the stability of monacolin K decreased with increasing the temperature. The stability for pH was in the order of the unadjusted pH (pH 5.9)>8>4 and pH 2>10. The stability for organic acid was high in the order of lactic acid>citric acid>acetic acid, and the stability of monacolin K under acid was different according to the acid type. The degradation rate of monacolin K increased with increasing the water content. Moreover monacolin K was able to isolate from red and pink pigments as well as the other noncoloric compounds in red yeast rice. The yield of monacolin K was found to be 70%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.2
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• pp.167-173
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• 2014

Red yeast rice (RYR) is the product of fermented yeast by Monascus strains on rice, and has recently become a popular dietary supplement as a traditional food in Asia. RYR contains monacolin K substances known to inhibit cholesterol synthesis as efficiently as statin drugs. To determine the optimal rice cultivar for manufacturing RYR, 7 rice cultivars (Goami, Goami2, Sangjuchalbyeo, Seolgaeng, Saegyejinmi, Yeonghojinmi and Chilbo) were fermented using two Monascus strains (M. ruber KCTC6122 and KCCM60141 of M. ruber) in this study. The monacolin K content of Sangjuchalbyeo were 47.24 ppm on KCTC6122 cultures and 117.03 ppm on KCCM60141 cultures, respectively. Other cultivars, especially Goami and Goami2, which had less content of monacolin K could not seem to ferment normally because those didn't show red color. These results imply that Sangjuchalbyeo can be optimal rice cultivar as a commercial RYR which is well fermented rice and has high content of monacolin K.

• Korean Journal of Food Science and Technology
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• v.35 no.2
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• pp.242-245
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• 2003

Buckwheat contains dietary rutin, a flavonol glycoside, which is able to antagonize hypertension in human and has antioxidant activity. Monacolin K, a secondary metabolite produced by fungi Monascus species, is an effective specific inhibitor of cholesterol biosynthesis. To develop functional health food, dehulled buckwheat was fermented with Manascus ruber to produce Anka, and contents of rutin and monacolin K and Anka were determined. The rutin content in dehulled buckwheat decreased slightly after germination, but increased with the growth of sprout. Growth of fungi had no influence on rutin content in dehulled buckwheat Anka, Monacolin K content in fermented dehulled buckwheat malt was lower than that in dehulled buckwheat Anka. Monacolin K content in dehulled buckwheat Anka decreased with increasing length of sprout in fermented dehulled buckwheat malt, probably due to consumption of nutrients, such as polysaccharides as carbon sources, during sprouting for growth of M. ruber.

• KSBB Journal
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• v.28 no.6
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• pp.400-407
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• 2013

The growth characteristics and production of color pigments by Monascus strains were investigated during liquid culture, and production of monacolin K in red mold rice was carried out by solid state fermentation. Four different Monascus ruber strains were cultured in potato dextrose yeast extract broth (PDYB) media at $25^{\circ}C$ for 15 days. The high producing strain for red pigment was not corresponded to the strain for yellow pigment. Production of red pigment was high in the strain causing the fast pH change in culture broth. Production of monacolin K in red mold rice by solid state fermentation was influenced by a combination of wet cell weight and spore density in inoculum by liquid culture. Most strains showed the high production of monacolin K in red mold rice, when submerged fermentation was carried out for 5 days as inoculum for solid state fermentation. These results suggest that submerged fermentation period of inoculum have an effect on the production of monacolin K in red mold rice by solid state fermentation, and monacolin K in red mold rice could be increased by controlling the condition of submerged fermentation for inoculum.

• Journal of Microbiology and Biotechnology
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• v.22 no.7
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• pp.975-980
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• 2012

Monacolin K-enriched ganghwayakssuk (Artemisia princeps Pamp.) was developed by fermentation with Monascus sp. Among the 15 Monascus spp. isolated previously from Monascus fermentation products, Monascus pilosus KMU108 produced 2,219 mg/kg of monacolin K during ganghwayakssuk fermentation with no detectable citrinin. The optimum concentrations of ganghwayakssuk and glucose determined from the response surface methodology (RSM) design were 2.2% and 3.8%, respectively. By applying these conditions, the monacolin K productivity was increased to 3,007 mg/kg after 15 days of fermentation. On the other hand, other characteristics such as the total content of flavonoids and phenolic compounds, and the antioxidant activity were relatively unchanged. Therefore, Monascus-fermented ganghwayakssuk is an excellent biomaterial for the development of functional foods because of its high level of monacolin K, known to lower cholesterol levels.

• KSBB Journal
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• v.23 no.6
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• pp.463-469
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• 2008

During the last decade, monacolin-K biosynthesized by fermentation of red yeast rice (Monascus strains) was proved to have an efficient cholesterol lowering capability, leading to rapid increase in the market demand for the functional red yeast rice. In this study, the production medium composition and components were optimized on a shake flask scale for monacolin-K production by Monascus pilosus (KCCM 60160). The effect of three different soybean flours on the monacolin-K production were studied in order to replace the nitrogen sources of basic production medium (yeast extract, malt extract and beef extract). Among the several experiments, the production medium with dietary soybean flour to replace a half of yeast extract was very good for monacolin-K production. Plackett-Burman experimental design was used to determine the key factors which are critical to produce the biological products in the fermentation. According to the result of Plackett-Burman experimental design, a second order response surface design was applied using yeast extract, beef extract and $(NH_4)_2SO_4$ as factors. Applying this model, the optimum concentration of the three variables was obtained. The maximum monacolin-K production (369.6 mg/L) predicted by model agrees well with the experimental value (418 mg/L) obtained from the experimental verification at the optimal medium. The yield of monacolin-K was increased by 67% as compared to that obtained with basic production medium in shake flasks.

• The Korean Journal of Food And Nutrition
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• v.14 no.6
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• pp.521-526
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• 2001

A method for the simultaneous and precise determination of lactone form and acid form monacolin K in red yeast rice by HPLC was developed in this study. The standard of acid form monacolin K was prepared by alkaline hydrolysis of its lactone form, which was purchased from Sigma company. The optimum HPLC system for the separation and quantification of acid form and lactone form monacolin K is based on the reversed-phase column, and the acidified mobile phase consisting of acetonitrile : 0.1% trifluoroacetic acid (TFA) water soln : 62 :38, the low limit detection amount was 5 ng (i.e.10 $\mu$l injection of 0.5 $\mu\textrm{g}$/ml) . And the optimal extracting system for monacolins in red rice was also presented here.