Enzymatic Synthesis of Fatty Acid Isoamyl Monoesters from Soybean Oil Deodorizer Distillate: A Renewable and Ecofriendly Base Stock for Lubricant Industries.

In this study, soybean oil deodorizer distillate (SODD), a mixture of free fatty acids and acylglycerides, and isoamyl alcohol were evaluated as substrates in the synthesis of fatty acid isoamyl monoesters catalyzed by Eversa (a liquid formulation of lipase). SODD and the products were characterized by the chemical and physical properties of lubricant base stocks. The optimal conditions to produce isoamyl fatty acid esters were determined by response surface methodology (RSM) using rotational central composite design (RCCD, 2 factorial + 6 axial points + 5 replications at the central point); they were 1 mol of fatty acids (based on the SODD saponifiable index) to 2.

Eucalyptus xylan: An in-house-produced substrate for xylanase evaluation to substitute birchwood xylan.

Over the past decades, most studies with xylanases have used Birchwood xylan as the standard substrate for activity assays. However, recently, Birchwood xylan production was discontinued by major suppliers, creating an important demand for a substitute. Ongoing and future studies require a substrate with characteristics equivalent to the discontinued xylan, in order to enable the comparison of results.

Oxygen transfer in a pressurized airlift bioreactor.

Airlift bioreactors (ALBs) offer advantages over conventional systems, such as simplicity of construction, reduced risk of contamination, and efficient gas-liquid dispersion with low power consumption. ALBs are usually operated under atmospheric pressure. However, in bioprocesses with high oxygen demand, such as high cell density cultures, oxygen limitation may occur even when operating with high superficial gas velocity and air enriched with oxygen.

Modeling the kinetics of complex systems: enzymatic hydrolysis of lignocellulosic substrates.

Lignocellulosic biomass is mainly composed of cellulose, hemicellulose, and lignin. Fuzzy logic, in turn, is a branch of many-valued logic based on the paradigm of inference under vagueness. This paper presents a methodology, based on computational intelligence, for modeling the kinetics of a complex reactional system.

Cloning, auto-induction expression, and purification of rSpaA swine erysipelas antigen.

This work reports the cloning, expression, and purification of a 42-kDa fragment of the SpaA protein from Erysipelothrix rhusiopathiae, the main antigenic candidate for a subunit vaccine against swine erysipelas. The use of an auto-induction protocol to improve heterologous protein expression in recombinant Escherichia coli cultures was also investigated. The cellular growth pattern and metabolite formation were evaluated under different induction conditions.

Intensification of high cell-density cultivations of rE. coli for production of S. pneumoniae antigenic surface protein, PspA3, using model-based adaptive control.

This work proposes an innovative methodology to control high density fed-batch cultures of E. coli, based on measurements of the concentration of dissolved oxygen and on estimations of the cellular specific growth rate (µ), of the yield of biomass/limiting substrate (Y (xs)) and of the maintenance coefficient (m). The underlying idea is to allow cells to grow according to their metabolic capacity, without the constraints inherent to pre-set growth rates.

Bioreactor aeration conditions modulate growth and antigen expression during Erysipelothrix rhusiopathiae cultivation.

Erysipelothrix rhusiopathiae, the causative agent of swine erysipelas, was cultivated in a 5-L stirred and aerated bioreactor under different dissolved oxygen tensions (0%, 5%, and 30% of saturation) for evaluation of the influence of oxygen on cell growth as well as on the production of the main antigenic component of the vaccine against erysipelas, a 64-69 kDa protein (SpaA). The microorganism presented different growth profiles for different aeration conditions. However, at the end of the batch cultivations, similar cell concentrations were obtained under the studied conditions.

The penicillin G acylase production by B. megaterium is amino acid consumption dependent.

Aiming at to enhance the production of penicillin G acylase (PGA) by Bacillus megaterium, we have performed flasks experiments using different medium composition. Using 51 g/L of casein hydrolyzed with Alcalase and 2.7 g/L of phenylacetic acid (PhAc), the following carbon substrates were tested, individually and combined: glucose, glycerol, and lactose (present in cheese whey).