Clarissa Daisy da Costa Albuquerque

Economic optimized medium for tensio-active agent production by Candida sphaerica UCP0995 and application in the removal of hydrophobic contaminant from sand.

Statistical experimental designs and response surface methodology were employed to optimize the concentrations of agroindustrial residues as soybean oil (SORR) from refinery, and corn steep liquor (CSL) from corn industry, for tensio-active agent produced by Candida sphaerica UCP 0995. Three 22 full factorial design were applied sequentially to investigate the effects of the concentrations and interactions of soybean oil refinery residue and corn steep liquor on the surface tension of free-cell culture broth for 144 h. Two 22 central composite designs and response surface methodology were adopted to derive a statistical model to measure the effect of SORR and CSL on the surface tension of the free-cell culture broth for 144 h. The regression equation obtained from the experimental data using a central composite design was solved, and by analyzing the response surface contour plots, the optimal concentrations of the constituents of the medium were determined: 8.63% v/v (≅9% v/v) of SORR and 8.80% v/v (≅9% v/v) CSL. The minimum surface tension predicted and experimentally confirmed was 25.25 mN/m. The new biosurfactant, denominated Lunasan, recovered 95% of motor oil adsorbed in a sand sample, thus showing great potential for use in bioremediation processes, especially in the petroleum industry.

Biosurfactant-and-Bioemulsifier Produced by a Promising Cunninghamella echinulata Isolated from Caatinga Soil in the Northeast of Brazil

A Mucoralean fungus was isolated from Caatinga soil of Pernambuco, Northeast of Brazil, and was identified as Cunninghamella echinulata by morphological, physiological, and biochemical tests. This strain was evaluated for biosurfactant/bioemulsifier production using soybean oil waste (SOW) and corn steep liquor (CSL) as substrates, added to basic saline solution, by measuring surface tension and emulsifier index and activity. The best results showed the surface water tension was reduced from 72 to 36 mN/m, and an emulsification index (E24) of 80% was obtained using engine oil and burnt engine oil, respectively. A new molecule of biosurfactant showed an anionic charge and a polymeric chemical composition consisting of lipids (40.0% w/w), carbohydrates (35.2% w/w) and protein (20.3% w/w). In addition, the biosurfactant solution (1%) demonstrated its ability for an oil displacement area (ODA) of 37.36 cm2, which is quite similar to that for Triton X-100 (38.46 cm2). The stability of the reduction in the surface water tension as well as of the emulsifier index proved to be stable over a wide range of temperatures, in pH, and in salt concentration (4%–6% w/v). The biosurfactant showed an ability to reduce and increase the viscosity of hydrophobic substrates and their molecules, suggesting that it is a suitable candidate for mediated enhanced oil recovery. At the same time, these studies indicate that renewable, relatively inexpensive and easily available resources can be used for important biotechnological processes.

Cometabolic Decolorization of the Reactive Azo Dye Orange II by Geobacillus stearothermophilus UCP 986

The decolorization of solutions containing the textile reactive dye Orange II by the bacteria Geobacillus stearothermophilus (UCP 986) was investigated. The experiments were statistically evaluated by two-level-four factor (2 4) full factorial design, as aeration, azo dye concentration, inoculum size, and culture media. The best results were with Luria Bertani (LB) medium under aeration, and the decolorization efficiency meant that 96—98% of the azo dye was removed after 24 h of incubation. The efficiency of LB medium in color reduction was due to a co-metabolic process. Sulphanilic acid (4-aminobenzene sulphonic acid) was not detected. The testing for toxicity using the brine shrimp Artemia salina showed the absence of toxic metabolites during the decolorization process; however, when the concentration of the dye and agitation were high (0.050 mM and 150 rpm) the shrimp showed high mortality rates (LC50 (lethal dose — assay concentration able to cause 50% of death) 49.28% v/v). The parameters such as culture medium and agitation are significantly important to the decolorization of the Orange II process. G. stearothermophilus (UCP 986) showed a high biotechnology potential for textile bioremediation of azo dye under the co-metabolic process.

Environmentally Friendly Biosurfactants Produced by Yeasts

Some yeasts are preferred to bacteria as sources for biosurfactants, mainly due to their GRAS status for environmental and health safety reasons. This chapter thus focuses on the production of biosurfactants by some yeast cultures using renewable resources like fatty wastes from household and vegetable oil refineries as major substrates. The chapter also emphasizes on the importance of the application of response surface methodology and artificial neural network techniques for the optimization of biosurfactant production by yeasts.

Enhancement of Cunninghamella elegans UCP/WFCC 0542 Biomass and Chitosan with Amino Acid Supply

Studies were carried out with Cunninghamella elegans UCP/WFCC 0542 to evaluate the effects of an abundant supply of amino acids, asparagine and corn steep liquor associated with sucrose on the production of biomass and chitosan by submerged fermentation. The concentrations of the components of the culture medium which were determined by a 23 full factorial design evaluated the interactions and effects of the independent variables of the sucrose, asparagine and corn steep liquor in relation to carbon and nitrogen sources, on the production of chitosan regarding biomass. The best results were observed at the central point [asparagine 0.025%, sucrose 0.15% and 0.45% of corn steep liquor, ratio C:N=2:6], and produced maximum yields of 16.95 g/L biomass and 2.14 g/L chitosan, after 96 h of submerged fermentation. However, the lowest level of sucrose, asparagine and corn steep liquor produced a low amount of biomass (10.83 g/L) and chitosan (0.60g/L). The infrared spectrum absorption of the chitosan produced by C. elegans showed bands regarding OH-axial stretching between 3406 and 3432 cm−1, superimposed on the NH stretching band with axial deformation of the amide C=O group at about 1639 cm−1, NH angular deformation at approximately 1560 cm−1; axial deformation of amide-CN at around 1421 cm−1, symmetrical angular deformation in CH3 at 1379 cm−1, -CN axial deformation of amino groups from 1125 to 1250 cm−1 and polysaccharide structure bands in the range of between 890–1150 cm−1. The crystallinity index of chitosan was 60.92%, and its degree of deacetylation was 75.25%. A low percentage of a supply of sucrose and asparagine with corn steep liquor offered higher yields of biomass and chitosan production at low cost.

On-line biomass estimation in biosurfactant production process by Candida lipolytica UCP 988

Biomass is an important variable in biosurfactant production process. However, such bioprocess variable, usually, is collected by sampling and determined by off-line analysis, with significant time delay. Therefore, simple and reliable on-line biomass estimation procedures are highly desirable. An artificial neural network model (ANN) is presented for the on-line estimation of biomass concentration, in biosurfactant production by Candida lipolytica UCP 988, as a nonlinear function of pH and dissolved oxygen. Several configurations were evaluated while developing the optimal ANN model. The optimal ANN model consists of one hidden layer with four neurons. The performance of the ANN was checked using experimental data. The results obtained indicate a very good predictive capacity for the ANN-based software sensor with values of R2 of 0.969 and RMSE of 0.021 for biomass concentration. Estimated biomass using the ANN was proved to be a simple, robust and accurate method.

Monitoring the effect of pyrene on the germination and radial growth of the wild and mutant strains of Rhizopus arrhizus UCP402

The physiological mutant of Rhizopus arrhizus was obtained in the pyrene resistance gradient test. Comparative studies were carried out about the behavior of the germination process and the radial growth of the mutant and wild strains of R. arrhizus UCP 402. Sabouraud Sucrose and Yeast Malt Broth cultures containing pyrene (10 mg/L) induced the germination process of the sporangiospores of the wild and mutant strains of R. arrhizus. The radial growth of the strains was inversely proportional to the pyrene concentration in the culture medium. The results showed an adaptation of R. arrhizus UCP 402x (mutant) in the pyrene (50mg/L) and suggested a higher ability of application in the removal of pyrene from the contaminated areas.