Unlocking the potential of biosurfactants: Production, applications, market challenges, and opportunities for agro-industrial waste valorization.

Biosurfactants are eco-friendly compounds with unique properties and promising potential as sustainable alternatives to chemical surfactants. The current review explores the multifaceted nature of biosurfactant production and applications, highlighting key fermentative parameters and microorganisms able to convert carbon-containing sources into biosurfactants. A spotlight is given on biosurfactants' obstacles in the global market, focusing on production costs and the challenges of large-scale synthesis. Innovative approaches to valorizing agro-industrial waste were discussed, documenting the utilization of lignocellulosic waste, food waste, oily waste, and agro-industrial wastewater in the segment. This strategy strongly contributes to large-scale, cost-effective, and environmentally friendly biosurfactant production, while the recent advances in waste valorization pave the way for a sustainable society.

Biosurfactant Production from Pineapple Waste and Application of Experimental Design and Statistical Analysis.

The use of non-conventional carbon sources for biosurfactant-producing microorganisms is a promising alternative in fermentation to substitute costly substrates. So, the current research used pineapple peel as a cost-effective and renewable substrate because of its rich composition in minerals and sugars and high availability. Following a 22 full factorial design, a bacterial strain of Bacillus subtilis produced biosurfactants in fermentative media containing different concentrations of glucose and concentrated pineapple peel juice (CPPJ). The influence of these two independent variables was evaluated according to three different responses: surface tension reduction rate (STRR), emulsification index (EI24), and concentration of semi-purified biosurfactant (SPB). The maximum value for STRR (57.63%) was obtained in media containing 0.58% glucose (w/v) and 5.82% CPPJ (v/v), while the highest EI24 response (58.60%) was observed at 2% glucose (w/v) and 20% CPPJ (v/v) and maximum SPB (1.28 g/L) at 3.42% glucose (w/v) and 34.18% CPPJ (v/v). Statistical analysis indicated that the CPPJ variable mostly influenced the STRR and SPB responses, whereas the EI24 was significantly influenced by pineapple peel juice and glucose contents.

Biosurfactants produced from corncob: a bibliometric perspective of a renewable and promising substrate.

The reuse of agro-industrial waste has been a recurring issue since the 20th century. With a composition rich in carbohydrates and because of the massive amount of residue produced daily all over the world, corncob became a low-cost and suitable substrate to produce high added-value compounds. Biosurfactants are bioproducts of versatile applications due to their chemical structure with hydrophilic and hydrophobic regions. The current work performed a bibliometric analysis to identify research related to the synthesis of biosurfactants using corncob as substrate. Despite the high availability of corncobs, only nine articles were found in Scopus and Web of Science using different pretreatment processes and microorganisms. After an initial screening, data regarding research organizations, scientific journals, citations, countries, institutions, and keywords were analyzed. Results indicated that corncobs were also used to produce enzymes, adsorbents, activated carbon, and furfural. The presented evaluation updated the status of art, identifying a serious need for more research, especially because of corncob's high potential to provide fermentable sugars and the wide range of variables influencing fermentation processes that still need to be studied. A future association of this low-cost substrate with other methods can result in a promising scenario for technology transference.

Potential of pineapple peel in the alternative composition of culture media for biosurfactant production.

The large pineapple's consumption and processing have generated a massive amount of waste yearly, which requires adequate treatment measures to avoid damages to the environment. Pineapple peel is one of the main residues obtained from this fruit and a promising strategy to take advantage of its potential is using it for biosurfactant production due to the peel's rich composition in fermentable sugars and nutrients, such as potassium and magnesium that favor the Bacillus subtilis growth and biosurfactant excretion as well. The current research performed a central composite design (CCD) with four independent variables (glucose, pineapple peel, potassium, and magnesium), evaluating substrates' influence on the surface tension reduction rate (STRR) and the emulsification index (EI24). The results indicated that pineapple peel has the necessary potential to act as a partial substitute for glucose and salt nutrients, minimizing the costs of supplementing with exogenous minerals. The highest surface tension reduction rate (57.744%) was obtained at 2.18% glucose (w/v); 14.67% pineapple peel (v/v); 2.38 g/L KH2PO4; and 0.15 g/L MgSO4.7H2O; whereas to obtain the maximum predicted value for EI24 (61.92%) the medium was composed by 2.24% glucose (w/v); 12.63% pineapple peel (v/v); 2.53 g/L KH2PO4; and 0.29 g/L MgSO4.7H2O.

Evaluation of a new strategy in the elaboration of culture media to produce surfactin from hemicellulosic corncob liquor.

The biosurfactant production is characterized by high costs with substrates, which does not make them sufficiently competitive against synthetic surfactants. The insertion of alternative sources of low cost, especially agro-industrial residue, is an excellent alternative to make this competitiveness viable. An alkaline pretreatment was used to extract the hemicellulose from corncob in order to enhance its C5 fraction, common to vegetable biomasses. The hemicellulosic corncob liquor was used with glucose and mineral salt solution as carbon and nutrients sources in a fermentation process for the growth of Bacillus subtilis. It was performed a 23 full factorial design to determine the best conditions for the surfactin production in relation to the following response variables: surface tension reduction rate (STRR) and emulsification index (EI24), from which were obtained two optimized bioproducts under specific conditions. The optimized biosurfactants found to be effected presenting a critical micelle concentration of 100 mg.L-1 and a maximum bioremediation potential of 85.18%, as well as maximum values of 57.38% and 65.30% for STRR and EI24 variables, respectively. Overall results pointed for a successful commercial application for the surfactin produced.