Improved lipid accumulation by morphology engineering of oleaginous fungus Mortierella isabellina

• Published in: Biotechnology and bioengineering Vol. 111; no. 9; pp. 1758 - 1766
• Main Authors: Gao, Difeng, Zeng, Jijiao, Yu, Xiaochen, Dong, Tao, Chen, Shulin
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.09.2014; Wiley Subscription Services, Inc
• Subjects: Biodiesel fuels; Bioengineering; Biofuels; Biotechnology - methods; Byproducts; Cell Adhesion; Dispersion; Fermentation; filamentous fungi; Fragments; Fuels; fungal morphology; Fungi; Glucose - metabolism; lipid accumulation; Lipid Metabolism; Lipids; Magnesium Silicates - metabolism; Microbiological Techniques - methods; microparticle; Microspheres; Morphology; Mortierella; Mortierella - drug effects; Mortierella - growth & development; Mortierella - metabolism; Mortierella - physiology; Mycelium - drug effects; Mycelium - growth & development; Mycelium - metabolism; Mycelium - physiology; oleaginous fungi; Pellets; filamentous fungi; biofuels; fungal morphology; lipid accumulation; oleaginous fungi; microparticle
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.25242

ABSTRACT Oleaginous fungi capable of accumulating a considerable amount of lipids are promising sources for lipid‐based biofuel production. The specific productivities of filamentous fungi in submerged fermentation are often correlated with morphological forms. However, the relationship between morphological development and lipid accumulation is not known. In this study, distinct morphological forms of oleaginous fungus Mortierella isabellina including pellets of different sizes, free dispersed mycelia, and broken hyphal fragments were developed by additions of different concentrations of magnesium silicate microparticles. Different morphological forms led to different levels of lipid accumulation as well as different spatial patterns of lipid distribution within pellets/mycelial aggregates. Significant higher lipid content (0.75 g lipid/g cell biomass) and lipid yield (0.18 g lipid/g glucose consumed) were achieved in free dispersed mycelia than in pellets. Moreover, extracellular metabolite analysis showed that production of undesirable by‐product malate was repressed in free dispersed mycelium form. Unveiling the desired morphological form of M. isabellina for lipid accumulation provided insights into molecular mechanism of lipid biosynthesis linked with morphological development, as well as design and optimization of bioprocess to produce lipid‐based biofuels. Biotechnol. Bioeng. 2014;111: 1758–1766. © 2014 Wiley Periodicals, Inc. The authors demonstrated that microparticle supplement was an effective approach to precisely control the morphology of oleaginous fungus Mortierella isabellina. The lipid accumulation and spatial distribution were correlated with morphological forms of pellets and mycelial aggregates. Free dispersed mycelium was the desirable form for obtaining a significant improvement in lipid productivity as well as repressed by‐product formation.