Optimization of Culture Conditions for Maximal Lovastatin Production by Aspergillus terreus (KM017963) under Solid State Fermentation

Exploitation of Sugarcane Bagasse and Environmentally Sustainable Production, Purification, Characterization, and Application of Lovastatin by Aspergillus terreus AUMC 15760 under Solid-State Conditions

Using the internal transcribed spacer (ITS) region for identification, three strains of Aspergillus terreus were identified and designated AUMC 15760, AUMC 15762, and AUMC 15763 for the Assiut University Mycological Centre culture collection. The ability of the three strains to manufacture lovastatin in solid-state fermentation (SSF) using wheat bran was assessed using gas chromatography-mass spectroscopy (GC-MS). The most potent strain was strain AUMC 15760, which was chosen to ferment nine types of lignocellulosic waste (barley bran, bean hay, date palm leaves, flax seeds, orange peels, rice straw, soy bean, sugarcane bagasse, and wheat bran), with sugarcane bagasse turning out to be the best substrate. After 10 days at pH 6.0 at 25 °C using sodium nitrate as the nitrogen source and a moisture content of 70%, the lovastatin output reached its maximum quantity (18.2 mg/g substrate). The medication was produced in lactone form as a white powder in its purest form using column chromatography. In-depth spectroscopy examination, including ¹H, ¹³C-NMR, HR-ESI-MS, optical density, and LC-MS/MS analysis, as well as a comparison of the physical and spectroscopic data with published data, were used to identify the medication. At an IC₅₀ of 69.536 ± 5.73 µM, the purified lovastatin displayed DPPH activity. Staphylococcus aureus and Staphylococcus epidermidis had MICs of 1.25 mg/mL, whereas Candida albicans and Candida glabrata had MICs of 2.5 mg/mL and 5.0 mg/mL, respectively, against pure lovastatin. As a component of sustainable development, this study offers a green (environmentally friendly) method for using sugarcane bagasse waste to produce valuable chemicals and value-added commodities.

Ultrasonic Irradiation Enables Facile Production of Lovastatin from Sugar Cane Bagasse

This study investigated the effect of ultrasound-assisted hydrogen peroxide (H₂O₂) pretreatment on sugar cane bagasse (SCB) followed by Monascus purpureus TISTR 3003 cultivation for lovastatin production under solid-state fermentation (SSF). Optimization of the pretreatment conditions was investigated using a response surface methodology (RSM). Within the range of the selected operating conditions, the optimized values of H₂O₂ concentration, amplitude, SCB dosage, and sonication time were found to be 2.74%, 83.22 μm, 2.84% and 52.29 min, respectively. The R ² value of 0.9749 indicated that the fitted model is in good agreement with the predicted and actual lovastatin production. On the basis of the optimum conditions, the lovastatin production was 2347.10 ± 17.19 μg/g, which is 2.4 times higher than that under untreated conditions. Scanning electron microscopy (SEM) analysis explored the surface structure of the untreated SCB, which showed a compact rigid structure. In contrast, treated SCB had a rough surface structure and cracks as a result of the pretreatment.

Lovastatin production by an oleaginous fungus, Aspergillus terreus KPR12 using sago processing wastewater (SWW)

Background

Lovastatin is one of the first statins to be extensively used for its cholesterol-lowering ability. It is commercially produced by fermentation. Species belonging to the genus Aspergillus are well-studied fungi that have been widely used for lovastatin production. In the present study, we produced lovastatin from sago processing wastewater (SWW) under submerged fermentation using oleaginous fungal strains, A. terreus KPR12 and A. caespitosus ASEF14.

Results

The intra- and extracellular concentrations of lovastatin produced by A. terreus KPR12 and A. caespitosus ASEF14 were lactonized. Because A. caespitosus ASEF14 produced a negligible amount of lovastatin, further kinetics of lovastatin production in SWW was studied using the KPR12 strain for 9 days. Lovastatin concentrations in the intra- and extracellular fractions of the A. terreus KPR12 cultured in a synthetic medium (SM) were 117.93 and 883.28 mg L–1, respectively. However, these concentrations in SWW were 142.23 and 429.98 mg L–1, respectively. The yeast growth inhibition bioassay confirmed the antifungal property of fungal extracts. A. terreus KPR12 showed a higher inhibition zone of 14 mm than the ASEF14 strain. The two-way analysis of variance (ANOVA; p < 0.01) showed significant differences in the localization pattern, fungal strains, growth medium, and their respective interactions. The lovastatin yield coefficient values were 0.153 g g–1 on biomass (YLOV/X) and 0.043 g g–1 on the substrate, starch (YLOV/S). The pollutant level of treated SWW exhibited a reduction in total solids (TS, 59%), total dissolved solids (TDS, 68%), biological oxygen demand (BOD, 79.5%), chemical oxygen demand (COD, 57.1%), phosphate (88%), cyanide (65.4%), and void of nutrients such as nitrate (100%), and ammonia (100%).

Conclusion

The starch-rich wastewater serves as a suitable medium for A. terreus KPR12 for the production of lovastatin. It simultaneously decontaminates the sago processing wastewater, enabling its reuse for irrigation/recreation.

Graphical Abstract

Production of poly (l-lactide)-degrading enzyme by Actinomadura keratinilytica strain T16-1 under solid state fermentation using agricultural wastes as substrate

Poly (l-lactide) (PLLA) is an aliphatic polyester that can be obtained from renewable resources and degraded by various microorganisms. In previous reports, Actinomadura keratinilytica strain T16-1 demonstrated high ability to degrade PLLA under various conditions. PLLA-degrading enzyme production under solid state fermentation has been sparsely studied. PLLA-degrading enzyme production by A. keratinilytica strain T16-1 was investigated using agricultural wastes as substrate under solid state fermentation (SSF). Three agricultural wastes as soybean meal, cassava chips and duckweed were tested as substrates for PLLA-degrading enzyme production by statistical methods using mixture design. Results revealed that using duckweed as the substrate gave the highest enzyme production (138.66 ± 13.57 U/g dry substrate). Maximum enzyme activity of 391.24 ± 15.57 U/g dry substrate was obtained under 10 g duckweed, 10% inoculum size, 7 days of cultivation time, pH 7.0, 2.8% PLLA powder, and 60% moisture content at 45 °C. It can be concluded that duckweed is an inexpensive substrate, which reduces the costs of PLLA-degrading enzyme production, as an alternative to effective water weed management.

An overview on the biosynthesis and metabolic regulation of monacolin K/lovastatin

Lovastatin/monacolin K (MK) is used as a lipid lowering drug, due to its effective hypercholesterolemic properties, comparable to synthetic statins. Lovastatin's biosynthetic pathway and gene cluster composition have been studied in depth in Aspergillus terreus. Evidence shows that the MK biosynthetic pathway and gene cluster in Monascus sp. are similar to those of lovastatin in A. terreus. Currently, research efforts have been focusing on the metabolic regulation of MK/lovastatin synthesis, and the evidence shows that a combination of extracellular and intracellular factors is essential for proper MK/lovastatin metabolism. Here, we comprehensively review the research progress on MK/lovastatin biosynthetic pathways, its synthetic precursors and inducing substances and metabolic regulation, with a view to providing reference for future research on fungal metabolism regulation and metabolic engineering for MK/lovastatin production.

The effects of solid-state fermentation on the content, composition and in vitro antioxidant activity of flavonoids from dandelion

Dandelion (Taraxacum officinale), a common plant worldwide, is used as both a medicine and food. Fermentation is a food processing technology that has many advantages, such as low energy cost, changes in product characteristics, and enhanced product quality. The purpose of this study was to investigate the effect of solid-state fermentation (SSF) on the content, composition and antioxidant activity of dandelion flavonoids. Response surface methodology was used to optimize dandelion fermentation conditions. Under optimized conditions, the maximum flavone concentration was 66.05 ± 1.89 mg/g. The flavonoid content of the crude extract from fermented dandelion (FDF) was 183.72 ± 2.24 mg/g. The flavonoid compounds in the crude extracts were further identified by UPLC-ESI-MS/MS. A total of 229 flavonoid compounds were identified, and 57 differential flavonoids (including 27 upregulated and 30 downregulated flavonoids) between FDF and the crude extract of unfermented dandelion (DF) were observed, of which 25 were annotated to metabolic pathways. FDF displayed superior antioxidant activity to that of DF in in vitro DPPH radical-scavenging and reducing power assays. The favorable results of our investigation could provide a new way for the exploitation and utilization of dandelion, which could be promising for its application as an antioxidant and functional food additive with flavonoids as ingredients.

Utilization of an Industry Byproduct, Corymbia maculata Leaves, by Aspergillus terreus to Produce Lovastatin

Due to its ability to lower cholesterol levels, simvastatin is a leading drug for the prevention of strokes and heart disease: it also lowers the incidence of neurodegenerative diseases. Simvastatin is made from lovastatin, a precursor produced by the industrial fungus, Aspergillus terreus. In this study, Corymbia maculata leaves were tested as a novel substrate for the growth of a new isolate of A. terreus and a lovastatin-resistant strain of A. terreus to produce lovastatin. Corymbia maculata (spotted gum) is well utilized by forest industries as a source of timber because of its high strength, durability and smooth texture. However, the leaves are a major waste product. Growth of A. terreus on Corymbia maculata leaves, in solid-state fermentation resulted in the production of lovastatin. Fermentation of media using fresh leaves of Corymbia maculata produced more lovastatin (4.9 mg g−1), than the sun-dried leaves (3.2 mg g−1). Levels of lovastatin were further increased by the lovastatin-resistant strain of A. terreus (Lvs-r), which produced twice the amount of the parental strain. The production of lovastatin was confirmed by HPLC and LC–MS/MS studies. The study suggests that the utilization of a cheap substrate for the production of lovastatin can have a potential economic benefit.

Lovastatin producing by wild strain of Aspergillus terreus isolated from Brazil

Lovastatin is a drug in the statin class which acts as a natural inhibitor of 3-hydroxy-3-methylglutaryl, a coenzyme reductase reported as being a potential therapeutic agent for several diseases: Alzheimer's, multiple sclerosis, osteoporosis and due to its anti-cancer properties. Aspergillus terreus is known for producing a cholesterol reducing drug. This study sets out to evaluate the production of lovastatin by Brazilian wild strains of A. terreus isolated from a biological sample and natural sources. Carbon and nitrogen sources and the best physicochemical conditions using factorial design were also evaluated. The 37 fungal were grown to produce lovastatin by submerged fermentation. A. terreus URM5579 strain was the best lovastatin producer with a level of 13.96 mg/L. Soluble starch and soybean flour were found to be the most suitable substrates for producing lovastatin (41.23 mg/L) and biomass (6.1 mg/mL). The most favorable production conditions were found in run 16 with 60 g/L soluble starch, 15 g/L soybean flour, pH 7.5, 200 rpm and maintaining the solution at 32 °C for 7 days, which led to producing 100.86 mg/L of lovastatin and 17.68 mg/mL of biomass. Using natural strains and economically viable substrates helps to optimize the production of lovastatin and promote its use.

Bioprospecting lovastatin production from a novel producer Cunninghamella blakesleeana

Beside anti-cholesterol activity, lovastatin garners worldwide attention for therapeutical application against various diseases especially cancer. A total of 36 filamentous fungi from soil samples were isolated and screened for lovastatin production by yeast growth bioassay method. C9 strain (later identified as Cunninghamella blakesleeana) was screened as potential strain of lovastatin production. Further confirmation of the compound was made using TLC, HPTLC and HPLC in which similar Rf value, densitogram peak and chromatogram peak against the standard lovastatin were observed, respectively. The purified lovastatin subjected for IR analysis showed a lactone ring peak at 1763.63 cm-1 similar to standard lovastatin. Further structural analysis including NMR and LC-MS of the purified lovastatin reassures the molecular formula and molecular weight similar to standard. In quantitative terms, C. blakesleeana, Aspergillus terreus and Aspergillus flavus produced 1.4 mg g-1 DWS, 0.83 mg g-1 DWS and 0.3 mg g-1 DWS of lovastatin, respectively, (p < 0.0001) without any optimization. Lovastatin showed significant antioxidant property with IC50: 145.9 µg mL-1 (140 µL), and the percentage of inhibition is maximum at 199.5 µg/mL which is statistically significant (p < 0.0001).

Optimization of thermostable organic solvent-tolerant lipase production by thermotolerant Rhizopus sp. using solid-state fermentation of palm kernel cake

This study enhanced the production of thermostable organic solvent-tolerant (TS-OST) lipase by locally isolated thermotolerant Rhizopus sp. strain using solid-state fermentation (SSF) of palm kernel cake (PKC). The optimum conditions were achieved using a series of statistical approaches. The cultivation parameters, which include fermentation time, moisture content, temperature, pH, inoculum size, various carbon and nitrogen sources, as well as other supplements, were initially screened by the definitive screening design, and one-factor-at-a-time using PKC as the basal medium. Three significant factors (olive oil concentration, pH, and inoculum size) were further optimized using face-centred central composite design. The results indicated a successful and significant improvement of lipase activity by almost two-fold compared to the initial screening production. The findings showed that the optimal conditions were 2% (v/w) inoculum size, 2% (v/w) olive oil, 0.6% (w/w) peptone, 2% (v/w) ethanol, 70% moisture content at initial pH 10.0 and 45 °C within 72 h of fermentation. Process optimization resulted in maximum lipase activity of 58.63 U/gram dry solids (gds). The analysis of variance showed that the statistical model was significant (p value <0.0001) and reliable with a high value of R² (0.98) and adjusted R² (0.96). This indicates a better correlation between the actual and predicted responses of lipase production. By considering this study, the low-cost PKC through SSF appears to be promising in the utilization of agro-industrial waste for TS-OST lipase production. This is because satisfactory enzyme activity could be attained that promises industrial applications.

Complete Genome Sequence of Soil Fungus Aspergillus terreus (KM017963), a Potent Lovastatin Producer

We report the complete genome of Aspergillus terreus (KM017963), a tropical soil isolate. The genome sequence is 29 Mb, with a G+C content of 51.12%. The genome sequence of A. terreus shows the presence of the complete gene cluster responsible for lovastatin (an anti-cholesterol drug) production in a single scaffold (1.16).