Lovastatin production by Aspergillus terreus using agro-biomass as substrate in solid state fermentation

Area of Science:

• Biotechnology
• Industrial Microbiology
• Natural Product Synthesis

Background:

• Lovastatin, a cholesterol-lowering drug, is primarily produced through fermentation.
• Solid-state fermentation (SSF) offers a sustainable approach for microbial metabolite production using agricultural byproducts.
• Investigating cost-effective substrates and optimizing fermentation conditions are crucial for efficient lovastatin biosynthesis.

Purpose of the Study:

• To evaluate the efficacy of rice straw (RS) and oil palm frond (OPF) as substrates for lovastatin production by Aspergillus terreus in SSF.
• To determine the optimal fermentation parameters, including nitrogen source, incubation temperature, moisture content, particle size, pH, and fermentation time, for maximizing lovastatin yield.
• To compare the lovastatin production capabilities of two Aspergillus terreus strains (ATCC 74135 and ATCC 20542) on selected substrates.

Main Methods:

• Solid-state fermentation (SSF) was conducted using two strains of Aspergillus terreus (ATCC 74135 and ATCC 20542) with rice straw (RS) and oil palm frond (OPF) as substrates.
• Various fermentation parameters were systematically varied, including nitrogen supplementation (soybean meal), incubation temperature, initial moisture content, particle size, pH, and fermentation duration.
• Lovastatin yield was quantified using established methods (mg/kg dry matter (DM)) and statistical analysis (P-values) was employed to assess the significance of different factors.

Main Results:

• Rice straw (RS) proved to be a superior substrate compared to oil palm frond (OPF) for lovastatin production in SSF.
• Aspergillus terreus ATCC 74135 achieved maximum lovastatin production of 157.07 mg/kg DM on RS without additional nitrogen.
• Optimized conditions (pH 6, 25°C, 1.4–2 mm particle size, 50% moisture, 8 days) yielded 175.85 and 260.85 mg/kg DM for ATCC 20542 and ATCC 74135, respectively, on RS.

Conclusions:

• Agricultural wastes like rice straw are viable and cost-effective substrates for industrial lovastatin production via SSF.
• Optimization of fermentation parameters significantly enhances lovastatin yield, demonstrating the potential of Aspergillus terreus for biotechnological applications.
• Further research into strain improvement and process scale-up could lead to more efficient and sustainable lovastatin manufacturing.