[Digestion] Hi

[Paul Harris]

G'day Dr A.D. Karve et al,

A number of years some students were investigating AD and feeding (I 
understand) just glucose - they wondered why the process kept stopping.

I do agree that the actual C:N ratio (like temperature and pH) is not 
critical, but must be somewhere in the range.

The combination of sugars etc without nitrogen and proteins or other 
feedstocks containing nitrogen is necessary to provide the necessary N , 
as I understood that the C:N ratio of most living things (microbes 
included) was approximately 25:1 (hence dung was also about 25:1). The 
composting fraternity has this quite well worked out.

We are learning all the time,
Happy digesting,

HOOROO
Mr Paul Harris

On 10-Jun-16 5:29 PM, Anand Karve wrote:
> Dear Paul,
> the so called ideal C/N value of 20 to 30 represents the C/N of cattle 
> dung, which is not an ideal feedstock. Almost 90% of the dry weight of 
> dung consists of non-digestible matter. Only the mucus and the load of 
> bacteria in the dung are digestible. I reproduce below the part of my 
> original article to clarify what I meant::
> Textbooks lay a lot of emphasis on a value called Carbon/Nitrogen 
> (C/N) ratio of the feedstock. The textbooks state 25 to be the ideal 
> C/N ratio. This is the C/N ratio of dung, but it is a relic of the 
> past when dung was universally considered to be the ideal feedstock. 
> It has already been discussed how dung, representing the effluent 
> slurry of a living biogas plant, can hardly be considered to be the 
> ideal feedstock. Sugars, starches, cellulose, fats and digestible 
> proteins show 100% digestibility.  Of these substances, sugars, 
> starches, cellulose and fats have C/N=*∞, *whereas the C/N ratio of 
> proteins is just 4 or 5. And yet, all of them show the v.s.% value of 
> 100. One should realize that as a living system, a biogas plant 
> requires all the inorganic components that a living cell needs, and 
> that it is illogical to take only the nitrogen content of the system 
> into consideration.
> Yours
> A.D.Karve
>
> ***
> Dr. A.D. Karve
>
> Chairman, Samuchit Enviro Tech Pvt Ltd (www.samuchit.com 
> <http://www.samuchit.com>)
>
> Trustee & Founder President, Appropriate Rural Technology Institute (ARTI)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/digestion_lists.bioenergylists.org/attachments/20160611/8746a14f/attachment.html>