Two methods for preparing universal microbial medium by eutectic system-based cellulose liquefaction

A method for preparing a carbon source for microbial medium, comprising:

• 1) mixing an ionic liquid and microcrystalline cellulose in a mass ratio of 5:3 to 10:1, wherein the ionic liquid is preheated at 70° C. to 90° C.;
• 2) mixing a mixed solution I obtained in step 1) and distilled water;
• 3) filtering a mixed solution II obtained in step 2), and collecting the filtrate;
• and
• 4) diluting the filtrate obtained in step 3) with distilled water to obtain the carbon source,
• wherein step 1) comprises:
• i) heating the mixed solution of the ionic liquid and the cellulose to 100° C. to 140° C., stopping the heating, then stirring;
• ii) heating the resulting mixed solution of step i) to 150° C. to 200° C., stopping the heating, then stirring;
• and
• iii) repeating step ii) three times, wherein the ionic liquid comprises 1-butyl-3-methylimidazolium chloride.