Statistical Design, a Powerful Tool for Optimizing Biosurfactant Production: A Review <s> Plackett-Burman <s> The nutritional medium requirement for biosurfactant production by Bacillus licheniformis K51 was optimized. The important medium components, identified by the initial screening method of Plackett-Burman, were H3PO4, CaCl2, H3BO3, and Na-EDTA. Box-Behnken response surface methodology was applied to further optimize biosurfactant production. The optimal concentrations for higher production of biosurfactants were (g/l): glucose, 1.1; NaNO3, 4.4; MgSO4 x 7H2O, 0.8; KCl, 0.4; CaCl2, 0.27; H3PO4, 1.0 ml/l; and trace elements (mg/l): H3BO3, 0.25; CuSO4, 0.6; MnSO4, 2.2; Na2MoO4, 0.5; ZnSO4, 6.0; FeSO4, 8.0; CoCl2, 1.0; and Na-EDTA, 30.0. Using this statistical optimization method, the relative biosurfactant yield as critical micelle dilution (CMD) was increased from 10x to 105x, which is ten times higher than the non-optimized rich medium. <s> BIB001 </s> Statistical Design, a Powerful Tool for Optimizing Biosurfactant Production: A Review <s> Plackett-Burman <s> In order to reduce production cost of Pseudomonas aeruginosa T1, which has the ability of producing the biosurfactant when using crude oil as the sole carbon source, Three experimental methodologies (Plackett-Burman design (PBD), steepest ascent design (SAD), Central composite rotatable design (CCRD)) were applied to optimize the medium ingredients of the strain. In the verification experiment, the surface tension (ST) of strain T1 fermentation decreased from 29.93mN/m to 27.08mN/m after medium optimization. <s> BIB002 </s> Statistical Design, a Powerful Tool for Optimizing Biosurfactant Production: A Review <s> Plackett-Burman <s> Surfactants are amphipathic molecules which reduce surface tension, widely used in pharmaceutical, cosmetic and food industries. The current study aimed to isolate Streptomyces species from Egyptian arid soil, efficient in biosurfactant production. Fifty isolates of Streptomyces were obtained from arid soil in Egypt. Primary screening, using lipase, drop collapse, parafilm M and haemolysis tests, showed 37 isolates (74%) having biosurfactant activity. Secondary screening resulted in 17 isolates based on their activities using emulsification index method. Isolate 5S was selected as the most efficient in biosurfactant production, having emulsification index equal to 31.74%. Plackett–Burman design was adopted to evaluate the factors affecting biosurfactant production. Among the tested nine variables of starch nitrate medium, treated molasses, peptone, Tween 80, incubation period and inoculum size were identified as significant factors affecting biosurfactant production. Cultivation of isolate 5S in the optimized medium elevated biosurfactant production to 42.68% (according to emulsification index) from 31.74%, obtained in un-optimized medium. <s> BIB003 </s> Statistical Design, a Powerful Tool for Optimizing Biosurfactant Production: A Review <s> Plackett-Burman <s> AbstractCosmetic products play an essential role in everyone’s life. People everyday use a large variety of cosmetic products such as soap, shampoo, toothpaste, deodorant, skin care, perfume, make-up, among others. The cosmetic industry encompasses several environmental, social and economic impacts that are being addressed through the search for more efficient manufacturing techniques, the reduction of waste and emissions and the promotion of personal hygiene, contributing to an improvement of public health and at the same time providing employment opportunities. The current trend among consumers is the pursuit for natural ingredients in cosmetic products, as many of these products exhibit equal, better or additional benefits in comparison with the chemical-based products. In this sense, biosurfactants are natural compounds with great potential in the formulation of cosmetic products given by their biodegradability and impact in health. Indeed, many of these biosurfactants could exhibit a “prebiotic” char... <s> BIB004
This is a specialized design for 2-31 factors where each factor is varied over two levels. It can be used if the absence of two-factor interactions can be assumed, otherwise a higher resolution factorial design is used. The PBD design is useful for testing ruggedness where little or no effect on the response due to the factors is expected. Thus, the first step needed to optimize the production of microbial metabolites can be done by screening the factors that affect the response of interest. The Plackett-Burman factorial design permits screening of numerous factors (without the interactions), including nutrients and physicochemical parameters, and thus, reduces the number of factors to be considered and analyzed in the subsequent optimization experiments BIB001  BIB002 . The PBD is a good option for starting optimization of Bs production since the number of factors influencing production are multifactorial, and optimal production depends not only on the source and concentration of nutrients for example, but also on the bacterial specie and strain studied. In a study carried out by Praharyawan et al.  , a PBD was used to optimize Bs production by 2+ and Mg 2+ negatively affected bacterial growth, and since bacterial growth was directly proportional to Bs production, high concentrations negatively affected Bs production. On the other hand, FeSO 4 ·7H 2 O positively affected Bs production, an observation that was in accordance to other reports on surfactin by other Bacillus strains. CaCl 2 ·2H 2 O showed a positive effect on Bs production and might have been related to its effect on the cell membrane. NaNO 3 and the frying oil waste were also essential for Bs production, and this was supported by the fact that there is a lot of evidence that suggests that these components are used as substrates for biosynthesis. Other interesting findings were the fact that KH 2 PO 4 had a negative effect on Bs production while K 2 HPO 4 favored production. The optimization of this culture medium resulted in a significant increase in Bs production by 124% compared to the standard non-optimized medium. Hassan et al. [33] , carried out PBD to optimize rhamnolipid production by two Pseudomonas sp. strains. The effects studied were carbon source, nitrogen source, C/N ratio, Fe 2+ concentration, Mg 2+ concentration, phenol toxicity, pH, temperature, shaking, and sampling time. The first design (evaluating carbon sources) allowed for an increase in Bs production in the range of 2-5 fold (depending on the strain), while the second design (carbon source concentration) showed no significant increase. For rhamnolipid synthesis, coconut oil had the greatest effect, while there was no discrimination in the nitrogen source for Bs synthesis. Low magnesium concentration favored Bs production suggesting that protein synthesis was blocked and cellular metabolism was shifted to carbohydrate synthesis and rhamnolipid production. This statistical design also revealed that for rhamnolipid production of these Pseudomonas strains, the physicochemical properties had a significant effect. Relatively low temperatures (30 • C), slight alkaline pH BIB004 , and high agitation favored Bs production. In another study, a PBD was used to optimize Bs production of Streptomyces sp. isolated from Egyptian arid soil. The most significant factors evaluated were starch nitrate medium, molasses, peptone, Tween 80, incubation period, and inoculum size, increasing emulsion by 13.5% BIB003 .