Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A Yeast Useful For Pollutant Removal Processes

28.06.2002


Sugar refineries and distilleries produce effluent which is harmful for the environment. The sugar industry produces two tonnes of sugar cane bagasse (a straw-like material) for every tonne of refined sugar. For Cuba this translates into 10 to 20 million tonnes of bagasse per year.



Distilleries, often associated with sugar cane production, emit copious amounts of polluting volatile components (especially volatile organic compounds, VOCs). In Cuba, an estimated annual 1 600 tonnes of ethanol, now the subject of control regulations, are released into the atmosphere. Stricter legislation recently introduced prompted many pieces of research to discover simple, cost-effective biological means of eliminating polluting elements from volatile emissions (biofiltration, biotrickling), which would be efficient enough to treat large volumes of even with low pollutant concentrations (about 1 g/m3).

A team from the IRD, in conjunction with the UAM (Mexico) and the ICIDCA (Cuba), has devised a laboratory-scale biofiltration system which can eliminate ethanol (along with smaller quantities of other possible VOCs ) emitted by distilleries, using sugar cane bagasse as support. The process involves passing the polluted air stream over a porous medium on which are fixed microorganisms preselected for their ability to decompose “target" compounds. Biofiltration is used successfully today at full industrial scale for controlling VOCs emissions from printing, certain branches of the food industry or for odour abatement at wastewater treatment plants.


The researchers first selected a yeast, Candida utilis, that could decompose ethanol, the organism’s only carbon source. Cultivation on a bed reactor followed, with the yeast growing directly on the bagasse which had been washed, sieved and sterilized. The bagasse is both solid and porous, allowing good circulation of polluted air, making it a good biofilter support. Inoculation with mineral salts, especially ammonium nitrate, helps increase the reactor’s degradation capacity. That salt brings nitrogen, which the yeast uses for increasing biomass and therefore for consuming more ethanol.

The team determined the optimal inlet ethanol concentrations needed to pass through the reactor for best biofilter efficiency. In suitable conditions, Candida utilis can rapidly decompose large quantities of ethanol. The yeast can thus eliminate up to 250 g of ethanol/hour/ m3 of the reactor. But any increase in ethanol loading rates must be gradual and doses of nutrient solution must be added stepwise. If the reactor is “overloaded” with ethanol, the yeast can no longer use, removal efficiency and elimination capacity drop abruptly and the system is blocked (1).

Candida utilis can be a prime remover simple molecules like ethanol from air. And a converter of waste into food, bagasse into balanced livestock feed. Its talent for harnessing the ethanol on bagasse and its naturally rich protein stock enables Candida utilis to enrich that material. The experiment achieved a 5.2 % protein concentration. Researchers are endeavouring to reach an even better figure. Whether or not the animals will accept this new forage remains to be confirmed. Indications are that they do, judging by trials under way in Cuba.

Ethanol biofiltration by Candida utilis has still to be investigated at larger scale and then at full industrial proportions. If successful, the process could be applied in other tropical countries which are major producers of sugar and alcohol, like Brazil, Cuba, Mexico and India.

(1) Yeast oxidizes ethanol, but not completely, converting it first into acetaldehyde, then acetic acid..

Marie-Lise Sabrie | alfa

More articles from Agricultural and Forestry Science:

nachricht Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli
26.04.2017 | University of the Basque Country

nachricht New data unearths pesticide peril in beehives
21.04.2017 | Cornell University

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>