Hi NT! what are the nutrients and the concentrations you can't dissolve? you just can't or they precipitate after autoclaving? if you are using distilled water you should be able to reproduce any solution. Try heating the suspensions while stirring.

cheers

Francisco

You can start with the organic waste without adding nutrients. If the growth is negative, you should optimize the medium adding different amiounts of Czapek-Dox or PD liquid media (for example 1/4, 1/2, 3/4... strenght)...

Article Optimization of Aspergillus niger rock phosphate solubilizat...

Good luck!

N.T. MARKAD: you wrote that you use as a substrate for a SSF of A. niger organic waste. I do not know what means organic wastes in your case, but if you employ for example food wastes, it would be feasible to perform their analyses (nitrogen, phosphorus, potassium, zinc, iron, .....) at first. The results may show, that addition of some elements is not needed at all. This could solve your problems

Best regards

Vit

Francisco Kuhar Sir, this is the concentration which I referred in one of the research paper for 1000ml;

1.Sucrose-10 g

2.Ammonium sulphate-5 g

3.Potassium dihydrogen phosphate- 2 g

4. Magnesium sulphate-1 g

5.Copper sulphate-1g

6.Iron sulphate-0.5 g

7.Zinc sulphate-1 g

8.Methanol- 10 ml

Hi N.T. MARKAD!

You should take into account the following circumstances:

1) you use an organic waste to produce citric acid in the SSF;

2) this material is rich with a carbon source but is limited in nitrogen;

3) to produce more citric acid you you need an abundant growth of fungus and readily available carbon source.

4) 10 g/l sucrose is too low concentration.

Therefore, for wetting of organic waste, I suggest you to use the following medium (g per 10 g of dry weight): KH2PO4 - 2.0, MgSO4 - 0.5, yeast extract - 4.0, peptone – 10.0, sucrose - 5.0. Try glycerol instead sucrose if it is an appropriate carbon source for the citric acid production. I assume that there is no need to supplement the above-indicated salts.

Best regards,

Vladimir

Dear colleague:

Firstly, if what you want is the production of citric acid through fermentation in the solid state by the fungus, you must take into account the type of substrate that you will use in your study, what characteristics it has and the nutrient contribution of it, however, for these purposes as well as you say you must include in the media compounds as Carbon Source (Glucose) and also as Nitrogen Source (Yeast extract). Now regarding the salts I advise you to do the following:

Prepare a more concentrated solution of microelements here I indicate it as they refer Madel & Reese:

FeSO4 x 7H2O ----- 50mg / L

MnSO4 x H2O ----- 1.6mg / L

ZnSO4 x 7H2O ----- 1.4mg / L

CoCl2 ------------------- 2mg / L

These components as you see are referred to 1L, from this concentrated solution take one ml and add it for every liter of medium

Remember that the medium must contain per liter (I do not know about your particular substrate but take this as an example):

Glucose --------------------------------- 10 g

 MgSO4 x 7 H2O --------------------- 0.3 g

L K2H (PO4) ----------------------------- 2 g

CaCl2 ----------------------------- ------ 0. 3 g

Yeast extract ------------------ 2 g

Bactopectone ------------------------- 0.1 g

And the solution of microelements ------ 1 ml

I hope this comment helps you and I also suggest that in the specific case of the production of citric acid by fermentation with the Aspergillus niger species, try to evaluates somo other different levels of these nutrients and in addition some other conditions, such as pH, agitation, temperature, metal ions, phosphate concentration, nitrogen and carbon source, alcohols and additives, because to optimize the process, these are important factors that regulate the morphology of the microorganism and the fermentation process.

I wish you the best.

Hi N T Markad

What solid organic waste you are using for solid state fermentation?

Depending upon the organic waste usage addition of mineral salts can be done in your media as per details mentioned by Maryen Alberto.

Coleman J., Ghosh S., Okoli I., Mylonakis E. Antifungal Activity of Microbial Secondary Metabolites. PLoS ONE, 2011; 6(9): e25321.

Hernández Guzmán P. Evaluación de la actividad antimicrobiana de metabolitos secundarios detectados en la fermentación líquida de una cepa nativa de Penicillium sp. SPG 64 aislada del páramo de Guasca, Cundinamarca. [Tesis de grado]. Bogotá: Grupo de Investigación en Fitoquímica, Pontificia Universidad Javeriana; 2012.

Jacometti N., Vieira M., Kenupp J. The potential of an Aspergillus fumigatus strain to produce antimicrobial secondary metabolites. Brazilian Journal of Microbiology 2005; 36: 357-362.

Jacometti N., Said S., Yoko I., Kenupp J. The antimicrobial activity of Aspergillus fumigatus is enhanced by a pool of bacteria. Microbiol. Res. 2002; 157: 207–211