Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Progress of arachidonic acid biosynthesis in microorganisms

29.05.2012
Single cell oils (SCO), produced by and extracted from some single-celled microorganisms, are featured with high levels of the major very long chain polyunsaturated fatty acids (PUFA).
SCO are essential for health and potential sources of bio-diesel. There has been a long history of interest in the exploitation of microorganisms as oil and fat providers, due to the continuing diminution of arable land and climate change making animal and plant sourced oils even more limited. However, such endeavor has been progressing hardly, mostly because the efficiencies of oil synthesis by microorganisms are normally too low to be applied in industry at a reasonable price.

The article "Ion-beam-mutation breeding of an arachidonic acid biosynthesis microorganism and its industrial fermentation control" , by Z. L. Yu and Q. Huang et al., from the Hefei Institutes of Physical Science, Chinese Academy of Sciences, published in Chinese Science Bulletin (2012) 57: 883, has started to shed light on this issue. Cells of the oil-producing fungus Mortierella alpine were genetically modified by their patented technology, known as ion beam biotechnology, and screened using procedures tailored for oil yield. They obtained one strain: 50% of its biomass was fatty acids, of which 70% is arachidonic acid.

In their report "Fats and oils in human nutrition" released in 1993, the FAO and WHO suggested that diet for infants, especially preterm infants and infants with insufficient breast-feeding, should be supplemented with adequate amounts of fatty acids with composition corresponding to fatty acids contained in breast-milk. AA and docosahexaenoic acid (DHA) are particularly important for brain development but only found in breast milk naturally. Therefore it has become a long-term focus developing AA-rich oil in microorganisms.

Over two decades ago, the authors started the project by implanting energetic ions, generated by an ion source and accelerated to certain electrical potentials, into cells of Mortierella alpine, the fungus naturally synthesizing PUFA. Implanted ions resulted in genetic mutations. They firstly screened for mutant cells producing high levels of total fatty acids, presumably resulting from mutations in genes controlling palmitic acid synthesis from acetyl CoA. In the second stage, established mutant strains from the first stage were mutated again by ion implantation and strains accumulating AA, among various kinds of fatty acids, were screened for. Such two-stage protocol was repeated until a genetically stable, AA-rich strain was obtained. Its AA yield was nearly 20 times of that of the original non-mutated strain, showing prospect of industrial application. The strain was transferred to manufacturer and a production line was thereafter constructed in Wuhan, by which fermentation control study was initiated.

Fermentation control normally involves optimization of culture media and growth condition, to reach a comprehensive and balanced nutrition supply for cell metabolism. To be used as diet supplement for infants, safety is the most critical issue therefore a simple media formulation guaranteeing minimum substrate residue was desired. Researchers tested the possibility of recycling the fungi residue after oil extraction into culture media. The "waste utilization" simplified culture media from 7 ingredients to just 2, glucose and the fungi residue, therefore reduced manufacturing costs. Data from 11 batches of fermentation in 200 m3 reactor with the minimum substrates showed that, the new strain reached an average biomass of 35.8 g/L (dry fungi cells/fermentation liquid), oil and AA contents of 18.4 g/L and 8.97 g/L respectively. This result attracted attention from more researchers.

Z. Cohen and C. Ratledge commented in their compilation "Single Cell Oils" that, "Alternative microbial sources of AA are also being sought. Already it is known there is a process for AA production in China, operated by Wuhan Alking Bioengineering Co. Ltd, using a new strain of Mortierella alpine. This process appears to operate at the 50-100 ton level."

Fatty acids from most microbial sourced oils have a similar composition with plant oils. Developing microbial oils is a promising direction for both bio-diesel industry and biological economy. The work and its related technologies reported here, such as cell modification by ion beams and recycling of fungi residue as substrate, not only developed new AA resource, but also offered new thoughts and paved a novel route for future exploration of microbial oil industry. This study has been supported by the 8th, the 9th and the 10th Five-Year National Science and Technology Plans (Projects 85-722-22-01˜a2001BA302B-04).

YU ZengLiang, WANG Ji, YUAN ChengLing, et al. Ion-beam-mutation breeding of an arachidonic acid biosynthesismicroorganism and its industrial fermentation control (in Chinese). Chinese Sci Bull(Chinese Ver), 2012, 11: 883-890.

Feng Huiyun | EurekAlert!
Further information:
http://www.ipp.ac.cn

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>