The dilemma for lipid productivity in green microalgae: importance of substrate provision in improving oil yield without sacrificing growth

10.1186/s13068-016-0671-2Biotechnology for Biofuels911-1

A high throughput screening and characterization of laccase-producing bacterium Serratia quinivorans AORB19 that exhibits lignin degradation traits, dye decolorization efficiency, and enhanced laccase production in biomass

Laccase (EC 1.10.3.2) assumes a vital role in the degradation of lignin by utilizing oxygen as an oxidant and catalyzing bond cleavage in both phenolic and nonphenolic lignin model compounds. However, their industrial application is limited due to reduced enzymatic activity and lower tolerance to extreme conditions in most laccases isolated from microorganisms. To address these challenges, bioprospecting for strains harboring novel laccases with enhanced activity and versatile properties is paramount. Natural biodegradation processes offer promises for lignin degradation, and rapid screening methods aid in isolating microorganisms secreting extracellular lignin-degrading enzymes, including laccases. In our study, we developed a novel high-throughput screening process to isolate a promising lignin-degrading bacterium from decomposed wood samples. Whole-genome analysis and LC-UV (Liquid Chromatography-Ultraviolet Detection) analysis was employed to identify the species and assess its lignin-degrading traits. This bacterium exhibited significant extracellular laccase production and was biochemically characterized. Moreover, the potential of this bacterium in bioremediation, specifically in the decolorization of two major dyes, was probed. Additionally, the laccase secretion capabilities of the bacterial strain were assessed by utilizing low-cost industrial wastes from the Canadian agro-industries. [...

PROMOTING LIPID PRODUCTIVITY AND FATTY ACID SECRETION IN MICROALGAE

Ph.DDOCTOR OF PHILOSOPH

Antimycobacterial activity of ascidian fungal symbionts

Biomedical Sciences: Molecular Biology and Human Genetic

A brief journey into the history of, and future sources and uses of fatty acids

The authors would like to thank the Engineering and Physical Sciences Research Council, University of St. Andrews, and the EPSRC Centre for Doctoral Training in Critical Resource Catalysis (CRITICAT) for financial support (Ph.D. studentship to MC; Grant code: EP/L016419/1).Fats and lipids have always had a primarily role in the history of humankind, from the ancient civilisations to the modern and contemporary time, going from domestic and cosmetic uses, to the first medical applications and later to the large scale industrial uses for food, pharmaceutical, cosmetics and biofuel production. Sources and uses of those have changed during time following the development of chemical sciences and industrial technological advances. Plants, fish and animal fats have represented the primary source of lipids and fats for century. Nowadays the use of fatty acid sources has taken a turn: industries are mainly interested in polyunsaturated fatty acids (PUFAs), which have beneficial properties in human health; and also, for high-value fatty acids product for innovative and green production of biofuel and feedstocks. Thus, the constant increase in demand of fatty acids, the fact that marine and vegetable sources are not adequate to meet the high level of fatty acids required worldwide and climate change, have determined the necessity of the search for renewable and sustainable sources for fatty acids. Biotechnological advances and bioengineering have started looking at the genetic modification of algae, bacteria, yeasts, seeds and plants to develop cell-factory able to produce high value fatty acid products in renewable and sustainable manner. This innovative approach applied to FAs industry is a peculiar example of how biotechnology can serve as powerful mean to drive the production of high value fatty acid derivatives on the concept of circular bioeconomy, based on the reutilisation of organic resources for alternative and sustainable productive patterns that are environmentally friendly.Publisher PDFPeer reviewe

26th Fungal Genetics Conference at Asilomar

Program and abstracts from the 26th Fungal Genetics Conference, March 15-20, 2011

Metabolic Engineering of oleaginous yeast for the production of biofuels

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2012.Cataloged from PDF version of thesis.Includes bibliographical references.The past few years have introduced a flurry of interest over renewable energy sources. Biofuels have gained attention as renewable alternatives to liquid transportation fuels. Microbial platforms for biofuel production have become an attractive option for this purpose, mitigating numerous challenges found in crop-based production. Towards this end, metabolic engineering has established itself as an enabling technology for biofuels development. In this work we investigate the strategies of metabolic engineering for developing a biodiesel production platform, utilizing the oleaginous yeast Yarrowia lipolytica as the host organism. We establish new genetic tools for engineering Y. lipolytica beginning with an expression vector utilizing the genetic features from translation elongation factor 1-a (TEF). Additionally, a complementary plasmid was developed allowing for multiple plasmid integration. Bioinformatics analysis of intronic genes in hemiascomycetous yeast also identified relationships between functional pathways and intron enrichment, chronicling the evolutionary journey of yeast species. Next gene targets were examined within the lipid synthesis pathway: acetyl-coA carboxylase (ACC), delta9-desaturase (D9), ATP citrate lyase (ACL), and diacylglycerol acyltransferase (DGA). A combinatorial investigation revealed the order of contribution to lipid overproduction (from strongest to weakest): DGA, ACC, D9, ACL. Scale-up batch fermentation of selected strains revealed exceptionally high lipid accumulation and yield. These results demonstrate the balance between cellular growth and lipid production which is being modified through these genetic manipulations. We next explored utilization of alternative substrates to expand the capabilities and utility of Y. lipolytica. For xylose, a prevalent substrate in cellulosic feedstocks, expression of the redox pathway from Scheffersomyces stipitis and adaptation led to successful substrate utilization. Through the use of cofermentation, growth and productivity on xylose was improved dramatically with xylose-to-lipids conversion successfully demonstrated. For acetate, a potentially useful substrate for electrofuel production, lipid production using our strongest performing strain resulted in high lipid accumulation and yield. From this study, metabolic engineering of Y. lipolytica was successfully used to achieve exceptional lipid overproduction from a variety of substrates. Our genetic tools and recombinant strains establish a strong platform for the study and development of microbial processes for the production of biofuels.by Mitchell Tai.Ph.D