Carlos André Veiga Burkert

The production of rhamnolipid by a Pseudomonas aeruginosa strain isolated from a southern coastal zone in Brazil.

The production and properties of a rhamnolipid-type biosurfactant, synthesized by the Pseudomonas aeruginosa LBM10 strain, isolated from a southern coastal zone in Brazil, were investigated. The assays were conducted in a rotary shaker at 30 degrees C and 180 rpm for a period of 96 h. Soybean oil and sodium nitrate were the best sources of carbon and nitrogen, respectively. A nitrogen-limiting condition (C/N ratio of 100) was favorable to biosurfactant production. The formation of stable emulsions was better in saline concentrations below 0.5%, pH values in the range from 6 to 9 and temperatures in the range from 35 to 40 degrees C, maintaining about 80% of its original activity for salinity up to 3% and 120 min of exposure at 100 degrees C. The biosurfactant may be produced with this microorganism using renewable substrates that are readily available, reaching values of 1.42 g l(-1) measured as rhamnose. This biosurfactant has interesting and useful properties for many industrial applications.

Extraction of carotenoids from Phaffia rhodozyma: A comparison between different techniques of cell disruption

The yeast Phaffia rhodozyma is known for producing carotenogenic pigments, commonly used in aquaculture feed formulation as well as in cosmetic, pharmaceutical, and food industries. Despite the high production of carotenoids from microorganisms by biotechnology, their use has limitation due to the cell wall resistance, which constitutes a barrier to the bioavailability of carotenoids. Therefore, there is a need to improve carotenoids recovering technique from microorganisms for the application of food industries. This study aimed to compare mechanical, chemical, and enzymatic techniques of cell disruption for extracting carotenoids produced by P. rhodozyma NRRL Y-17268. Among the techniques studied, the highest specific concentration of carotenoids (190.35 μg/g) resulted from the combined techniques of frozen biomass maceration using diatomaceous earth and enzymatic lysis at pH of the reaction medium of 4.5 at 55°C, with initial activity of β-1,3 glucanase of 0.6 U/mL for 30 min.

Technological process for cell disruption, extraction and encapsulation of astaxanthin from Haematococcus pluvialis

In this work, the effectiveness of different enzymatic techniques for cell wall disruption of Haematococcus pluvialis for the extraction of carotenoids and subsequent encapsulation of extracts in the co-polymer poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) using the Solution Enhanced Dispersion by Supercritical fluids (SEDS) technique was investigated. Glucanex(®) performed best compared with Lyticase(®) and Driselase(®). The conditions for enzymatic lysis using this enzyme preparation were established as a pH of 4.5, a temperature of 55 °C, an initial activity of β-1,3-glucanase of 0.6 U mL(-1) and a reaction time of 30 min. Enzymatic lysis assisted by ultrasound without biomass freezing was shown to be a promising and simple one-step technique for cell wall disruption, reaching 83.90% extractability. In the co-precipitation experiments, the highest encapsulation efficiency (51.21%) was obtained when using a higher biomass to dichloromethane ratio (10 mg mL(-1)) at the carotenoid extraction step and a lower pressure of precipitation (80 bar). In these conditions, spherical particles in the micrometer range (0.228 μm) were obtained.

Bioproduct Extraction From Microbial Cells by Conventional and Nonconventional Techniques

Abstract Demands of the food industry for sustainability have increased interest in microbial processes, which may yield bioproducts, such as pigments, lipids, proteins, biopolymers, enzymes, and carbohydrates, besides other bioactive molecules and ingredients from renewable feedstocks. The main focus of research and development has been the determination of cultivation parameters. However, intracellular bioproduct extraction from cells is a crucial step of the process, because it should aim at high yield, mitigation of environmental impacts, easy scale-up, economic feasibility, and integration in the downstream process. In this chapter, the main goals are to review conventional and nonconventional techniques involved in the physicochemical extraction of bioproducts from fungi, bacteria, and microalgae, and to describe their benefits and constraints. Techniques, such as supercritical fluid and ultrasound-assisted extraction are discussed, as well as emerging technologies, such as microwave-assisted extraction, pulsed electric fields, and organic solvent-free systems.

Cell Disruption of Chaetoceros calcitrans by Microwave and Ultrasound in Lipid Extraction

Downstream processing, such as cell disruption and extraction, constitutes a key step in microalgal-based industrial bioprocesses, mainly due to high costs and environmental impact. In this context, extraction technologies need to be improved, including the use of nonconventional cell disruption techniques suitable for scale-up, such as microwave and ultrasound. Therefore, this study aimed at investigating the effects of different methods of cell disruption (microwave and ultrasound) on lipid extraction from biomass of the diatom Chaetoceros calcitrans cultured in mixotrophic conditions in a medium with natural sea water and residual glycerol, with different treatment times. Both techniques applied to the biomass were efficient; that is, the results were 24.6 ± 1.3% lipids (ultrasound for 5 min) and 24.2 ± 0.9% lipids (microwave for 40 s), with no significant differences between them ( ). Likewise, there was no significant difference regarding the chemical disruption with hydrochloric acid 2 M as control (24.2 ± 1.0%). The ultrasound method consumed less energy than the microwave method. Both cell disruption methods applied to the biomass resulted in changes in the fatty acid profiles, that is, percentages of saturated fatty acids increased from 7.7% (control) to 16.6% (microwave) and 15.5% (ultrasound), whereas polyunsaturated ones increased from 12.8% (control) to 22.8% (microwave) and 21.8% (ultrasound). Concerning monounsaturated fatty acids, percentages decreased from 79.5% (control) to 60.6% (microwave) and 62.7% (ultrasound).

Rheological, textural and emulsifying properties of an exopolysaccharide produced by Mesorhizobium loti grown on a crude glycerol-based medium

In the present study, a new extracellular polysaccharide (EPS-M816) was obtained during the growth of Mesorhizobium loti Semia 816 on a crude glycerol-based medium. EPS-M816 precipitate mainly consisted of carbohydrates (82.54%) and proteins (11.31%), and the weight average molecular weight was estimated at 1.646 × 106 Da. The biopolymer was characterized by FT-IR and NMR spectroscopy, and was found to have typical functional groups of other rhizobial polysaccharides. Furthermore, the rheological and emulsifying properties were investigated. The EPS-M816 solution (1.0% w/v) showed typical pseudoplastic non-Newtonian fluid behavior, and the addition of sodium and potassium chloride (1 mol L-1) increased the apparent viscosity. Regarding its emulsification activity, EPS-M816 formed emulsions with different food-grade vegetable oils (soybean, rice, canola, sunflower and corn oils), showing emulsification index values over 65% in 24 h, indicative of strong emulsion-stabilizing capacity. The biopolymer was able to form gels with texture parameters similar to those reported for xanthan gum and low syneresis. Overall, these results suggest that EPS-M816 is a good candidate for application in the food, cosmetics and pharmaceutical industries as a thickening, gelling, stabilizing and emulsifying agent.