Method of producing biosurfactants

Abstract

The present invention relates to a method of producing biosurfactants, such as surfactin, comprising culturing at least one biosurfactant-producing microbe in a liquid culture medium comprising vinasse as a carbon source. Methods of using the crude biosurfactant containing culture broth in tertiary oil recovery and as antibacterial compositions in tertiary oil recovery are also described. Methods of using the culture broth residue after isolation of the biosurfactants as fertilizer and compositions for this use are also described.

1 . A method of producing biosurfactant comprising culturing at least one biosurfactant-producing microbe in a liquid culture medium comprising vinasse as a carbon source, wherein the culturing occurs at pH 6 to 8 and a temperature of 25° C. to 40° C. 
     
     
         2 . A method of  claim 1  wherein the at least one biosurfactant-producing microbe is selected from the group consisting of  Bacillus subtilis, Bacillus licheniformis, Bacillus amyloliquefaciens, Bacillus pumilus, Bacillus popilliae , RSA-203 and mixtures thereof. 
     
     
         3 . A method of  claim 2  wherein the at least one biosurfactant-producing microbe is selected from the group consisting of  Bacillus subtilis, Bacillus licheniformis  and mixtures thereof. 
     
     
         4 . A method of  claim 2  wherein the  Bacillus subtilis  is  Bacillus subtilis  NRRL B-3383,  Bacillus subtilis  RSA-203 or mixtures thereof. 
     
     
         5 . A method of  claim 2  wherein the at least one biosurfactant-producing microbe comprises a mixture of  Bacillus subtilis  and  Bacillus licheniformis.    
     
     
         6 . A method of  claim 1  wherein the vinasse is sugar cane vinasse. 
     
     
         7 . A method of  claim 1  wherein the vinasse is present in the liquid culture medium in an amount of from 3 to 10% w/v. 
     
     
         8 . A method of  claim 1  wherein the biosurfactant is selected from the group consisting of surfactin, iturin, lichenysin, fengycin and mixtures thereof. 
     
     
         9 . A method of  claim 8  wherein the biosurfactant is surfactin. 
     
     
         10 . A method of  claim 1  wherein the temperature is 30° C. to 35° C. 
     
     
         11 . A method of  claim 1  wherein the pH is 6.5 to 7.2. 
     
     
         12 . A method according to  claim 1  wherein the liquid culture medium is inoculated with an inoculum of at least one biosurfactant-producing microbe to provide an initial optical density at 600 nm  of 1.2 to 1.4 
     
     
         13 . A method of  claim 1  wherein the liquid culture medium further comprises a catabolizable nitrogen source. 
     
     
         14 . A method of  claim 13  wherein the catabolizable nitrogen source is an ammonium salt. 
     
     
         15 . A method of  claim 14  wherein the ammonium salt is ammonium nitrate. 
     
     
         16 . A method of  claim 1  wherein the liquid culture medium further comprises at least one inorganic salt. 
     
     
         17 . A method of  claim 16  wherein the at least one inorganic salt is a sulfate, chloride or phosphate of manganese, sodium or iron, or mixtures of said salts. 
     
     
         18 . A method of  claim 1  wherein the culturing further comprises aerating the liquid culture medium during culturing and collecting foamate produced during aeration. 
     
     
         19 . A method of  claim 18  wherein aeration is begun before the culturing is begun. 
     
     
         20 . Biosurfactant produced by the method of  claim 1 . 
     
     
         21 . A composition comprising at least one biosurfactant-producing microbe and vinasse residue, wherein the vinasse residue is formed by decomposition of vinasse by biosurfactant-producing microbes during a culturing process. 
     
     
         22 . A composition of  claim 21  further comprising at least one biosurfactant. 
     
     
         23 . A composition of  claim 22  wherein the biosurfactant is selected from surfactin, lichenysin, iturin, fengycin or mixtures thereof. 
     
     
         24 . A composition of  claim 23  wherein the biosurfactant is surfactin. 
     
     
         25 . A composition of  claim 21  further comprising a microbial food source. 
     
     
         26 . Use of a composition of  claim 21  in tertiary oil recovery. 
     
     
         27 . Use of a composition of  claim 21  as an antibacterial composition to protect equipment from corrosion during tertiary oil recovery or natural gas high pressure well processing. 
     
     
         28 . Use according to  claim 27  wherein the natural gas high pressure well processing is water fracking. 
     
     
         29 . Use of a composition of  claim 21  as a fertilizer. 
     
     
         30 . A method of tertiary oil recovery comprising
 i. treating an oil well with a composition comprising a biosurfactant, and   ii. treating the oil well with a composition according to  claim 21 .