GB1220807A - Production of fermentation and cultivation media - Google Patents

Abstract

1,220,807. Degraded vegetable matter. NATIONAL RESEARCH DEVELOPMENT CORP. 8 May, 1968 [17 May, 1967], No. 22872/67. Heading C1B. [Also in Division C6] In a process for degrading vegetable matter to produce a nutrient culture medium for the cultivation of micro-organisms (bacteria, moulds, higher fungi and actinomycetes) involving the use of an aqueous acidic reagent followed by an aqueous alkaline reagent or vice versa, the first reagent is applied to the vegetable matter in a degradative treatment which extracts carbonaceous matter into the aqueous phase to produce a first extract, and the second reagent either is combined with the first extract or is used to extract further carbonaceous matter from the residue of the first treatment to produce a second extract which is then combined with the first extract, and the two reagents together provide the whole or at least the greater part of two or more of the elements phosphorus, sulphur and nitrogen (optionally, potassium also) required in the final medium. The vegetable matter, consisting mainly of cellulose, hemicellulose and lignin, is exemplified by cereal straws and husks (wheat, maize, oat or rice), corn cobs, sawdust and wood waste, beet tops, sugar cane bagasse and cacao shells, waste byproducts from the processing of fruits and vegetables, potato haulms, pea vines and shells, ground nut shell and skin, coffee parchment and grounds, bracken and certain species of water weed. The degradative treatments are carried out with a solution of the reagent in a quantity not greater than three times the amount required for complete wetting of the vegetable material, and at temperatures of up to 100‹ C. for up to 10 hours, or as high as 121‹ or 150‹ C. for up to 3 hours. The following reagents may be employed:- phosphoric acid or acid phosphate (as source of phosphorus) sulphuric acid (sulphur) nitric acid, ammonia or urea (nitrogen) Hydrochloric acid, sodium or potassium hydroxide or carbonate, calcium and magnesium hydroxides, and small quantities of Fe, Mn and Zn in the form of their salts, may also be used. The treatments with the reagents are conducted in a closed system. The material may, however, be steeped in air between successive treatments. The nutrient medium obtained may be liquid or semi-solid. The residue remaining after preparing the extract may be dispersed in the extract, used as a medium for the surface growth of micro-organisms, or solubilized separately by treating with alkali and then oxidizing. Microorganisms suitable for growth on the prepared media are those which do not require the whole of their carbon source in the form of a sugar and particularly those micro-organisms for which a source of organic nitrogen is not essential. According to one typical example, 10 g. of unground oat husks are steeped overnight in 45 ml. of 1% phosphoric acid and the acid extract is set aside. The residue, partially dried by heating, is steeped overnight in 40 ml. of alkali reagent (10 g. NaOH + 10 g KOH per 100 ml.) and after spreading out into a thin layer is heated for 1 hour at 60‹ C. and exposed to air for 24 hours at room temperature. The clear thick liquid obtained by adding 150 ml. of water and constituting the alkali extract is combined with the acid extract and the pH of the combined medium is adjusted to 5À5. The final volume is made up to 600 ml. to give a concentration of oat husk extract in the medium equal to 1À25% (73% extraction). An alternative procedure involves degrading separate parts of the material with acid and alkali, respectively, and combining the degraded products. The nutrient media are tested by the cultivation of such micro-organisms as Tricholoma nudum, Agaricus campestris and Boletus luteus to produce mushroom tissue utilizing a reciprocatory shaker of 1 inch stroke (100 strokes per minute) or a rotary shaker (250 r.p.m.).