Biotechnology advances in β-carotene production by microorganisms

Beta-Carotene, a type of carotenoid commonly found in plants, fungi and algae, is the most common and stable natural pigment found in nature. β-Carotene can be converted into vitamin A in the human body, where it exerts oxidation resistance, anticancer activity and anticardiovascular properties. β-carotene has therefore been widely used in food, medicine and the nutrition industry. To date, natural β-carotene is mainly extracted from plants, algae and microorganisms that can naturally accumulate β-carotene, which has the disadvantages of a high price, long growth cycle and low yield. With the development of metabolic engineering and the deepening of research related to the synthetic pathway of β-carotene, the use of metabolic engineering plays an important role in increasing the yield of β-carotene, providing another route for its production. This review covers the biosynthetic pathways of β-carotene and the production of β-carotene by naturally accumulating microorganisms and microbial metabolic engineering. Moreover, different metabolic engineering strategies and the accumulation levels of various microorganisms are considered. In addition, this paper also advances the prospect of the microbial production of β-carotene, especially the development of the production of β-carotene by microbial metabolic engineering. β-Carotene can be extracted from plants, algae and other natural resources, which has the disadvantages of environmental pollution and high production costs. In nature, in addition to plants and algae, microorganisms, such as some fungi and bacteria, can also synthesize β-carotene. At present, there are many reports on the production of β-carotene by microbial metabolic engineering, which has the advantages of low environmental pollution, low production costs and a high yield in addition to broad development prospects. To date, the major microorganisms used in the bioengineering of β-carotene metabolism are Escherichia coli and yeast. It is a feasible strategy to establish a plant to produce β-carotene by using metabolic engineering technology and optimizing the fermentation of engineered strains.