Potassium biphthalate buffer for pH control to optimize glycosyl hydrolase production in shake flasks using filamentous fungi

The optimization of culture medium with statistical methods is widely used in filamentous fungi glycosyl hydrolase production. The implementation of such methodology in bioreactors is very expensive as it requires several pH-controlled systems operating in parallel in order to test a large number of culture media components. The objective of this study was to evaluate potassium biphthalate buffer for pH control, which allows the optimization studies to be performed in shake flasks.The results have shown that buffering the culture medium with 0.1 M potassium biphthalate allowed pH control, resulting in a decrease of the standard deviation of triplicates for pH and activities of glycosyl hydrolase measurements. The use of this buffer allowed shake flask culture media optimization of enzyme production by Trichoderma harzianum, increasing the cellulase activity by more than 2 times compared to standard unbuffered culture medium. The same buffer can be used for culture media optimization of other fungi, such as Penicillium echinulatum342439450CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informaçã

Produção biotecnológica de poli-hidroxialcanoatos para a geração de polímeros biodegradáveis no Brasil

In recent years, several studies have been developed in Brazil to produce biodegradable materials. A particular family of bacterial polymers, the polyhydroxyalkanoates (PHA), has received special attention. PHAs are thermoplastic, biodegradable, biocompatible, are synthesised from renewable resources and can substitute petrochemical plastics in some applications. Different aspects have been focused to increase productivity and to reduce the cost of PHA production: bacterial improvement, use of industrial by-products as raw material, bioreactor design, process operation strategies, downstream process, mathematical modelling, polymer characterisation, application and biodegradability of blends. A production process was transferred to industry and studies to produce new PHA by controlling monomer composition are in progress. All these aspects are presented in this review

Mathematical modeling of enzyme production using Trichoderma harzianum P49P11 and sugarcane bagasse as carbon source

A mathematical model to describe the kinetics of enzyme production by the filamentous fungus Trichoderma harzianum P49P11 was developed using a low cost substrate as main carbon source (pretreated sugarcane bagasse). The model describes the cell growth, variation of substrate concentration and production of three kinds of enzymes (cellulases, beta-glucosidase and xylanase) in different sugarcane bagasse concentrations (5; 10; 20; 30; 40 g L−1). The 10 g L−1 concentration was used to validate the model and the other to parameter estimation. The model for enzyme production has terms implicitly representing induction and repression. Substrate variation was represented by a simple degradation rate. The models seem to represent well the kinetics with a good fit for the majority of the assays. Validation results indicate that the models are adequate to represent the kinetics for a biotechnological process198101107FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2012/19271-

Mathematical modelling for the optimization of cellulase production using glycerol for cell growth and cellulose as the inducer substrate

Cellulase production can be divided into two steps: growth stage; followed by an induction stage. To develop a mathematical model for the optimization of this strategy, two sets of experiments were performed in batch mode for parameter estimation. One set of experiments was performed to evaluate the influence of glycerol regarding cell growth (initial concentrations of 5, 10, 15 and 20 g/L). The other set of experiments considered the induction stage using cellulose as the substrate (initial concentrations of 5, 10, 20, 30 and 40 g/L). Two feeding strategies were simulated to maximize cellulase production using glycerol to maintain a high cell concentration. The first simulation used a discrete feed and the second used a continuous feed of cellulose. The mathematical model proposed allows maintaining a high cell concentration and the addition of optimal small amounts of the inducer substrate to prevent inhibition of enzyme production.</p

Adsorption characteristics of cellulase and β‐glucosidase on Avicel, pretreated sugarcane bagasse, and lignin

Although adsorption is an essential step in the enzymatic hydrolysis of lignocellulosic materials, literature reports controversial results in relation to the adsorption of the cellulolitic enzymes on different biomasses/pretreatments, which makes difficult the description of this phenomenon in hydrolysis mathematical models. In this work, the adsorption of these enzymes on Avicel and sugarcane bagasse pretreated by the hydrothermal bagasse (HB) and organosolv bagasse (OB ) methods was evaluated. The results have shown no significant adsorption of β‐glucosidase on Avicel or HB. Increasing solids concentration from 5% (w/v) to 10% (w/v) had no impact on the adsorption of cellulase on the different biomasses if stirring rates were high enough (>100 rpm for Avicel and >150 rpm for HB and OB). Adsorption equilibrium time was low for Avicel (10 Min) when compared with the lignocellulosic materials (120 Min). Adsorption isotherms determined at 4 and 50 °C have shown that for Avicel there was a decrease in the maximum adsorption capacity ( Emax) with the temperature increase, whereas for HB increasing temperature increased Emax. Also , Emax increased with the content of lignin in the material. Adsorption studies of cellulase on lignin left after enzymatic digestion of HB show lower but significant adsorption capacity ( Emax = 11.92 ± 0.76 mg/g)625681689CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informação2011/02743‐

Data of added-value lipid production, Arachidonic acid, among other lipids by Mortierella elongata, using low cost simulated wastewater

This article presented an innovative data of feasibility to produce Arachidonic acid (ARA), as added-value Polyunsaturated Fatty Acids (PUFA), among other lipids from Mortierella elongata, using simulated low cost sugarcane wastewater, vinasse, as a carbon source. Data from lipids quantification by total lipids extraction and by lipid classes was presented. M. elongata was able to produce 156.45mg of ARA per g of total lipids

Controle da biossíntese de poli-hidroxialcanoatos bacterianos através do fluxo de substratos Control of the biosynthesis of bacterial polyhydroxyalkanoates through the flux of substrates

<abstract language="eng">Manipulation of the flux of substrates was utilized to control the amount of 3-hydroxyvalerate and 3-hydroxy-4-pentenoate produced by Burkohlderia sp. The 3HV production rate was directly proportional to the propionic acid uptake rate with the last one completely directed to 3HV biosynthesis. The 3HPE production rate was inversely proportional to the sucrose uptake rate probably due to operation of the glyoxylate cycle

Continuous production of enzymes under carbon-limited conditions by trichoderma harzianum P49P11

Carbon-limited chemostat cultures were performed using different carbon sources (glucose, 10 and 20 g/ L; sucrose, 10 g/L; fructose/glucose, 5.26/5.26 g/L; carboxymethyl cellulose, 10 g/L; and carboxymethyl cellulose/glucose, 5/5 g/L) to verify the capability of the wild type strain Trichoderma harzianum to produce extracellular enzymes. All chemostat cultures were carried out at a fixed dilution rate of 0.05 h1 Experiments using glucose, fructose/glucose and sucrose were performed in duplicate. Glucose condition was found to induce the production of enzymes that can catalyse the hydrolysis of p nitrophenyl-b-D-glucopyranoside (PNPGase). A concentration of 20 g/L of glucose in the feed provided the highest productivity (1048 ± 16 U/mol h). Extracellular polysaccharides were considered the source of inducers. Based on the obtained results, a new PNPGase production process was developed using mainly glucose. This process raises interesting possibilities of synthesizing the inducer substrate and the induced enzymes in a single step using an easily assimilated carbon source under carbon-limited conditions