Crude glycerol from biodiesel industry as substrate for biosurfactant production by Bacillus subtilis ATCC 6633

Abstract

Glycerol, a co-product of the biodiesel industry, may be a suitable raw material for the production of high addedvalue compounds by the microorganisms. This study aimed to use the glycerol obtained from the biodiesel production process as the main carbon source for biosurfactant production by Bacillus subtilis ATCC 6633. Results indicated that the strain lowered the surface tension of the cell-free fermented broth to 31.5 ± 1.6 mN/m, indicating the production of biosurfactant. The critical micelle concentration (CMC = 33.6 mN/m) obtained was similar to the previously reported for biossurfactants isolated from otherBacillus. The produced biosurfactant was able to emulsify n-hexadecane and soybean oil.

Comparative study: bench-scale surfactin production from bacillus subtilis using analytical grade and concentrated glycerol from the biodiesel industry

“…This obviously indicates that in both cases good biosurfactant production and recovery was obtained. For both culture media (AGG and CGBP), the ST remained constant ≈ 34 mN/m, after 24 h, which is similar to reported by Sousa et al [5] 31.5 mN/m after 72 h of fermentation. In this sense, CMD-2 remained also constant ≈ 72 mN/m data.…”

“…The literature describes the production of surfactin per liter of culture medium (glucose as carbon source and extracted direct from the culture medium) to be at least 500 mg/L, whereas using glycerol as carbon source, lower yields are usually described (158.14 mg/L after 72 h of fermentation) [5], [19][20]. The production with AGG medium was ≈ 325 mg of surfactin/liter of culture medium, whereas with the CGBP medium was 71 mg/L.…”

“…Thus, in years to come, due to increasing biodiesel production the price of glycerol will tend to decrease. Glycerol is a fermentable polyol (sugar alcohol) nutrient for most bacteria and yeasts [5][6]. In addition, depending on the source of triglycerides used in biodiesel production, raw glycerol can contain nutritional elements such as phosphorous, sulfur, magnesium, calcium, nitrogen and sodium, which can be used by microorganisms in the fermentation process [7].…”

“…At the same time the use of glycerol from biodiesel industry could improve the profitability of biodiesel in a broader sense for biorefineries. However, a few papers have detailed surfactin production from Bacillus subtilis using glycerol from biodiesel production as carbon source such as Sousa et al [5], Sousa et al [3], Sousa et al [4], De Faria et al [13]. In particular, there is a lack of knowledge on the effect of glycerol purity on productivity.…”

<b>Biosurfactants produced by <i>Microbacterium</i> sp., isolated from aquatic macrophytes in hydrocarbon-contaminated area in the Rio Negro, Manaus, Amazonas

“…The absorption peaks were similar to those observed by Jara, Andrade, and Campos-Takaki (2013) and Sousa et al (2014) when characterizing a tensoactive agent produced by Geobacillus stearothermophilus and a biosurfactant produced by B. subtilis, respectively. Camacho-Chab et al (2013) studying the genus Microbacterium isolated from marine environment reported the production of glycoproteins able to emulsify aromatic hydrocarbons and oils.…”