A blog from University of Borås

Saturday, March 21, 2015

Vietnamese Rice Wine with Snake Taste

People in Vietnam are used to drink beer and spirit. As I heard, in the rural area, it is very common to drink and take rest in the afternoon. The statistics by WHO shows that males (not females) of age 15+ drink more than 27 liter equivalent pure alcohol per year.

Rice wine (with ca 45-50% alcohol content) is a common drink. In addition, they believe if they keep snakes in this alcohol solution for a while it makes you stronger. If the snake is more dangerous and you keep it longer, then the drink become better!

But the processing of this drink with very simple equipment (home distillery) is interesting. Here I put some photos that I took from Mekong region in Vietnam:

1- They soak rice mixed with Baker's yeast (it means the enzymes become active)

2- They put it in jars and keep it for a while (fermentation occurs)

3- Distillation of the fermented mash to collect alcohol (obtaining 45-50% alcohol in water)

4- Kill the snakes and put it immediately in the alcohol and keep it for a while!

5- Cheers!

Sunday, March 15, 2015

Greenhouse gas emissions in 2014

This week came the news about the global greenhouse gas (GHG) emissions in 2014 that was 32.3 billion tonnes. It was the same as the year before although we have a global economical growth by 3%.  It is a very good news that shows a positive development to reduce the global warming. However, I believe it is not enough.

As I wrote before, this level of GHG emission is about 50% more than the capacity of the earth to reabsorb the gases and we should reduce it to less than 20 billion tons per year. In addition, with the current oil price, it is hard to believe that this positive trend remains in 2015. Nowadays, the biofuels have difficulties to compete with the cheap fossil fuels and it will affect the GHG emissions in the next statistics. Anyway, let's enjoy this little positive little news for the time being!

Wednesday, March 11, 2015

Ethanol ED95 for diesel trucks

Ethanol is well known as an additive or substitute for cars with gasolines. For this purpose, hydrous ethanol (e.g. less than 95% ethanol and the rest is water) is dehydrated to ethanol with 99% purity and mixed with gasoline.

Now, ethanol is also produced commercially for diesel engines. Diesel engines have a high compressions and use no ignitions. In order to match these properties,  hydrated ethanol (e.g. 95%) is supplemented with about 5% additives to obtain ED95. This mixture has about 92% ethanol, ca 4% water and 4% other additives. It is produced now by Agroetanol here in Sweden and is being used by light trucks (26-tons with 270 hp bioethanol engines) in Stockholm. Such trucks are about 10,000-15,000 USD more expensive than diesel trucks as the engines need different compressions. The examination of these trucks show an average reduction of 68-85% GHG emission compared to fossil fuels. I wish good luck with this work!

Tuesday, November 11, 2014

Tasty or deadly fruits: A PhD thesis!

Fruits is probably just something to eat. But, it has a special function in reproduction of the trees by carrying the seeds. The fruits should be on trees for a some weeks or months and keep safe against the continual bacterial attacks. That is where the flavors comes into the picture. One of their important functions is to keep the fruits safe until matured.

We have globally more than 400 million tons fruits waste every year, that is perfect to be converted to biogas and produce energy. However, these flavors can become problem and when you put them in the reactor, they can kill the cells even in very low concentrations. What are these flavors, how toxic they are and how to treat them, is a subject of PhD thesis by Rachma Wikandari. She is defending her thesis in a couple of weeks on 27 Nov. Here is the details of her work:

PhD thesis: Effect of fruit flavors on anaerobic digestion: inhibitions and solutions

and publications:

1. Inhibitory effects of fruits flavors on methane production during anaerobic digestion

2. Ester compounds on biogas production: beneficial or detrimental? 

3. Effect of Ketone, Lactone, and Phenol on Methane Production and Metabolic Intermediates during Anaerobic Digestion

Monday, October 13, 2014

PhD thesis: Simultaneous Saccharification, Fermentation and Filtration (SSFF)

Our PhD student Mofoluwake Ishola will defend her thesis on "Novel application of membrane bioreactors in lignocellulosic ethanol production : simultaneous saccharification, filtration and fermentation (SSFF)" on 31 October. She had nailing today which an old tradition (since 1517 by Martin Luther). In this ceremony, the candidate nail the thesis on a tree as you can see in the photo.

The thesis was about fermentation of lignocellulosic materials. She developed a method that combines the traditional methods of enzymatic hydrolysis and fermentation named Simultaneous saccharification and fermentation (SSF) and separation hydrolysis and fermentation (SHF) to this new method called SSFF. Using membranes are the heart of this development.  You can read more about it in her thesis, or publications: 

Simultaneous saccharification, filtration and fermentation (SSFF): A novel method for bioethanol production from lignocellulosic biomass
Effect of high solids loading on bacterial contamination in lignocellulosic ethanol production,
Effect of Fungal and Phosphoric acid Pretreatment on Ethanol production from Oil Palm Empty Fruit Bunches (OPEFB)
Biofuels in Nigeria: A critical and strategic evaluation,

Saturday, June 7, 2014

Cooking egg on biogas from palm oil residuals

I have recently visited our projects in Indonesia that deals with biogas from palm oil residuals. At a palm oil plant in Borneo, FOV Biogas installed a 100 m3 pilot that is producing biogas from POME (palm oil mill effluent) in a textile reactor. In a parallel project, in a lab textile reactor at Gadjah Mada University, OPEFB (Oil Palm Empty Fruit Bunches) are converted to biogas. Our Indonesian student (Luki) with his colleague are happily cooking egg for their lunch from the biogas that they have produced  from OPEFB. I tasted the egg, and it was quite good :)

(The students are cooking egg from the biogas produced in textile reactor from OPEFB. You can see some OPEFB on the reactor)

(The textile reactor for converting biogas from POME)

Tuesday, April 1, 2014

A shortcut to commercial second generation ethanol using fungi

Ethanol is produced today by the 1st generation processes, e.g. from sugarcanes in Brazil or grains in the USA. It is now about 3 decades with intensive research and development on the 2nd generation ethanol from lignocelluloses, but the process is not commercial yet.

We have a concept to integrate the lignocelluloses into the 1st generation ethanol plants from grains by filamentous fungi, a concept that we are developing since 1999. It means, several hundreds of dry mils (ethanol from grain processes) can already start producing ethanol from lignocelluloses with principally very low investment. By this integration, ethanol and animal feed are produced from stillage (wastewater of the process) and also added lignocelluloses materials. The concept is now examined in large fermentors in the large ethanol plant in Sweden (Agroetanol) and can hopefully make the lignocelluloses ethanol closer to commercial market. You can download the scientific publication about it here!

Saturday, March 15, 2014

Membranes Bioreactor or capsules for ethanol production? A PhD thesis

On 4th April, our PhD student Päivi Ylitervo will defend her thesis. She had the goal to develop rapid fermentation of toxic wood hydrolyzates for ethanol production. Her work was in parallel of another PhD study on "Suiciding yeast" that I mentioned last month. She worked on capsules in half of her work, and then focused on membrane bioreactors for ethanol production. It is an interesting and novel work, considering the membrane bioreactors are developed principally for wastewater treatment. It gives a new application for such bioreactors. Let's wish her good luck in her defense!

Her thesis on "Concepts for improving ethanol productivity from lignocellulosic materials: encapsulated yeast and membrane bioreactors", can be found here!

Some of her publications:

Päivi Ylitervo, Carl Johan Franzén, Mohammad J. Taherzadeh,(2011), Ethanol production at elevated temperatures using encapsulation ofyeast, Journal of Biotechnology, 156, 22 – 29

Päivi Ylitervo, Carl Johan Franzén, MohammadJ. Taherzadeh, (2013), Mechanically robust polysiloxane-ACA capsulesfor prolonged ethanol production, Journalof Chemical Technology & Biotechnology, 88, 1080–10

Päivi Ylitervo, Carl Johan Franzén, Mohammad J. Taherzadeh, (2013),Impact of furfural on rapidethanol production using a membrane bioreactor, Energies, 6,1604-1617

Päivi Ylitervo, Julius Akinbomi,Mohammad J. Taherzadeh (2013), Membrane bioreactors’ potential for ethanol and biogas production: Areview, Environmental Technology, 34: 1711–1723 

Sunday, March 2, 2014

A PhD thesis on Membranes for bioreactors

This week, we will have our third PhD defense in three weeks (one defense per week). The last two defenses went quite well, and I hope this last one will also go well. This time, our PhD student Hamidreza Barghi will defend his thesis that is about making membranes for membrane bioreactors. These membranes are quite specific. They have to retain the cells, while being permeable to the cells feed (substrates) and their products (metabolites), the gases (such as CO2, and methane), and they have to resist the harsh conditions in the reactors.

The thesis can be downloaded here!

Sunday, February 9, 2014

Why big digesters for biogas? A PhD thesis

If you have seen biogas processes, you have probably noticed very big vessels for the biogas productions. They are normally 100-10,000 m3 in size. The reason of this big size is that the materials should stay in the reactors for about 30 days. The bugs that do the job and produce biogas are sensitive and need long time to grow. Just as example, you can compare E. coli bacteria that can duplicate itself in 20 minutes, while a methane producing bacteria (or archaea) need about 2 weeks to duplicate. It means if you don't want them to get away from the reactor, you should have big vessels, feed it slowly and let them to stay longer than two weeks.

In a PhD thesis that will be defended 27 Feb. 2014, Solmaz Aslanzadeh found a method to reduce this retention time from about 30 days to about 6 days! It means if her results can be applied commercially, the biogas digesters will squeeze by 80% in their size. You can read her thesis to see how she did it:

Thesis title: Pretreatment of cellulosic waste and high rate biogas production