ABSTRACT
Yarrowia lipolytica is a non-conventional yeast with unique physiological and metabolic characteristics. It is suitable for production of various products due to its natural ability to utilize a variety of inexpensive carbon sources, excellent tolerance to low pH, and strong ability to secrete metabolites. Currently, Y. lipolytica has been demonstrated to produce a wide range of carboxylic acids with high efficiency. This article summarized the progress in engineering Y. lipolytica to produce various carboxylic acids by using metabolic engineering and synthetic biology approaches. The current bottlenecks and solutions for high-level production of carboxylic acids by engineered Y. lipolytica were also discussed, with the aim to provide useful information for relevant studies in this field.
Subject(s)
Carboxylic Acids/metabolism , Metabolic Engineering , Synthetic Biology , Yarrowia/metabolismABSTRACT
In recent years, adaptive laboratory evolution (ALE) has emerged as a powerful tool for basic research in microbiology (e.g., molecular mechanisms of microbial evolution) and efforts on evolutionary engineering of microbial strains (e.g., accelerated evolution of industrial strains by bringing beneficial mutations). The ongoing rapid development of next-generation sequencing platforms has provided novel insights into growth kinetics and metabolism of microbes, and thus led to great advances of this technique. In this review, we summarize recent advances in the applications of long-term and short-term ALE techniques mainly for microbial strain engineering, and different modes of ALE are also introduced. Furthermore, we discuss the current limitations of ALE and potential solutions. We believe that the information reviewed here will make a significant contribution to further advancement of ALE.
Subject(s)
High-Throughput Nucleotide Sequencing , Laboratories , MutationABSTRACT
Limonene (C₁₀H₁₆) and bisabolene (C₁₅H₂₄) are both naturally occurring terpenes in plants. Depending on the number of C₅ units, limonene and bisabolene are recognized as representative monoterpenes and sesquiterpenes, respectively. Limonene and bisabolene are important pharmaceutical and nutraceutical products used in the prevention and treatment of cancer and many other diseases. In addition, they can be used as starting materials to produce a range of commercially valuable products, such as pharmaceuticals, nutraceuticals, cosmetics, and biofuels. The low abundance or yield of limonene and bisabolene in plants renders their isolation from plant sources non-economically viable. Isolation of limonene and bisabolene from plants also suffers from low efficiency and often requires harsh reaction conditions, prolonged reaction times, and expensive equipment cost. Recently, the rapid developments in metabolic engineering of microbes provide a promising alternative route for producing these plant natural products. Therefore, producing limonene and bisabolene by engineering microbial cells into microbial factories is becoming an attractive alternative approach that can overcome the bottlenecks, making it more sustainable, environmentally friendly and economically competitive. Here, we reviewed the status of metabolic engineering of microbes that produce limonene and bisabolene including microbial hosts, key enzymes, metabolic pathways and engineering of limonene/bisabolene biosynthesis. Furthermore, key challenges and future perspectives were discussed.