METHOD OF PRODUCING BIOSURFACTANTS
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 .