[Digestion] Microlagae feedstock

[Duncan Martin]

Mr Karve is right about the protein.

Microalgae were once strongly promoted as sources of single-cell protein 
(SCP), which we were assured would solve the world's food problems. Their 
protein content is very high.

Unfortunately, starving people are as reluctant as the well-fed to eat 
wholly novel foods - and I recall that these SCP products tasted anything 
but appetizing. There was talk of blending them with other stuff, to 
"dilute" the taste - but it all petered out. SCP can also be high in nucleic 
acids, which could lead to toxicity problems if SCP was a major component of 
the diet.

I think the economics were unhelpful too. It's hard to undercut 
"industrially farned" soya.

So I'd be surprised if microalgae were too high in C to digest well. They 
might even be too high in N - but a mixed feedstock would solve that one.

However, as so often, I find myself questioning the basic premise of a 
proposal. If you have tonnes of microalgae that you need to dispose of, AD 
might be a good idea. But why use an expensive  multistep process (growth of 
algae, harvesting, AD), all using large-scale costly equipment (albeit with 
low running costs) to convert solar energy into biogas energy? Even if land 
is so cheap that lagoons cost little, you might do better to cover it in 
solar panels and get your energy directly.

Duncan

----- Original Message ----- 
From: "adkarve" <adkarve at pn2.vsnl.net.in>
To: <DIGESTION at listserv.repp.org>
Sent: Sunday, June 03, 2007 7:14 AM
Subject: Re: [Digestion] Microlagae spriulina feedstock


> Dear David,
> as far as I know, green and blue-green algae are full of nitrogen, quite
> comparable to green leaves. One dry weight basis, Spirulina contains 70%
> protein.
> Yours
> A.D.Karve
> ----- Original Message -----
> From: David Fulford <d.j.fulford at reading.ac.uk>
> To: jc clerc <jc_clerc at hotmail.com>; <socrate at hatoum.com>;
> <buffiere at supagro.inra.fr>
> Cc: <DIGESTION at LISTSERV.REPP.ORG>; <kopiske at utec-bremen.de>;
> <michael.thomm at biologie.uni-regensburg.de>
> Sent: Friday, June 01, 2007 9:35 PM
> Subject: Re: [Digestion] Microlagae spriulina feedstock
>
>
>> Jean- Charles and all, Hi
>>
>> As the language of the list is English, I will use that language. My
> French
>> is very poor.
>>
>> Microalgae would make a good additive for the biogas process, especially
> if
>> other feedstocks had reasonable levels of nitrogen. The carbon content of
>> microalgae is probably too high for therm to be used as a single feed.
>>
>> You could make a solar-powered generation system, by growing the algae,
>> using the effluent of the biogas digester as a growth medium and then
>> feeding the algae into the digester. The nitrogen would be recycled. I
>> suspect the area of land (actually lagoon) to do this would be a problem.
>> People have grown microalgae in long plastic tubes on vertical frames to
>> reduce space, so it might be a possible way forward.
>>
>> Cheers,
>>
>> David
>>
>> At 11:22 01/06/2007 +0200, jc clerc wrote:
>> >Bonjour,
>> >
>> >Je me permet de vous contacter (via mon inscription sur le site
>> >http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org)
> pour
>> >simplement savoir si les microalgues type Spirulina sont une bonne 
>> >option
>> >pour la production de Methane via digester.
>> >
>> >Hello,
>> >I am taking the chance to contact you (via my inscription on the website
>> >http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org) 
>> >in
>> >order to know if microalgae like  Spirulina are the right feedstock in
> order
>> >to produce Methane thru Digester.
>> >
>> >Kind regards
>> >Jean-charles CLERC
>> >algoil project (www.algoil.com)
>> >jc_clerc at hotmail.com
>> >+33611833157
>> >
>>
>> *** Dr David Fulford, MSc Renewable Energy, Engineering Building ***
>> ***     School of Construction Management and Engineering        ***
>> ***      The University of Reading, Whiteknights,                ***
>> ***    Reading RG6 6AY, UK      Tel: +44-(0)118-378 8563,        ***
>> *** Fax: +44-(0)118-931 3327 E-mail: D.J.Fulford at Reading.ac.uk   ***
>>
>>
>> _______________________________________________
>> Digestion mailing list
>> Digestion at listserv.repp.org
>> http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org
>
>
> _______________________________________________
> Digestion mailing list
> Digestion at listserv.repp.org
> http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org
> Beginner's Guide to Biogas
> http://www.adelaide.edu.au/biogas/
> http://info.bioenergylists.org
>
>
>
> -- 
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.472 / Virus Database: 269.8.5/826 - Release Date: 31/05/2007 
> 16:51
>
>