Optimización multi-objetivo en procesos biotecnológicos : aplicación al cultivo de células vegetales en suspensión de Thevetia peruviana

RESUMEN: La productividad de los bioprocesos es un compromiso entre dos objetivos en conflicto, la maximización de la velocidad de crecimiento de la biomasa y la minimización del consumo de sustrato. En este trabajo, se resuelve un problema de optimización multi-objetivo para mejorar la productividad del cultivo en suspensión de células vegetales de la especie Thevetia peruviana. La solución del problema multi-objetivo permitió determinar las concentraciones iniciales óptimas de sustrato y biomasa para garantizar la máxima productividad. La optimización se lleva a cabo utilizando un modelo mecanistico, que incluye una representación de los procesos intracelulares que tienen lugar en las células vegetales. Las mejores soluciones se eligieron del frente de Pareto teniendo en cuenta el criterio experto. Los resultados indican que se recomienda una concentración inicial de inóculo de 3.91g/L y una concentración inicial de sacarosa de 23.63g/L como condiciones iniciales para obtener una productividad de biomasa de 1.57g/L*día con un consumo aceptable de sacarosa. Se llevó a cabo la validación experimental del óptimo encontrado y la productividad obtenida fue de 1.52g/L usando una concentración de inóculo inicial de 4.27g/L y una concentración inicial de sacarosa de 25.44g/L. Los resultados sugieren que la metodología propuesta puede ampliarse para aumentar la productividad en términos de producción de metabolitos a partir de estos cultivos de células vegetales y otras especies vegetales.ABSTRACT: Bioprocesses productivity is a compromise between two conflicting objectives, maximization of biomass growth rate and minimization of substrate consumption. In this work, a model based multi-objective optimization problem is solved for improving the process productivity in plant cell suspension cultures of Thevetia peruviana. A solution of the multi-objective problem allowed determining the optimal initial concentrations of substrate and biomass for assuring maximal productivity. Model-based optimization is carried out using a mechanistic model, which includes a representation of the intracellular processes taking place on the plant cells. The best solutions were chosen from the Pareto front in agreement with expert criterion. Results indicate that an initial inoculum concentration of 3.91g/L and an initial sucrose concentration of 23.63g/L, are recommended as initial conditions for obtaining a biomass productivity of 1.57g/L*day with an acceptable sucrose uptake. Experimental validation of the optimal found was carried out and the productivity obtained was 1.52g/L using an initial inoculum concentration of 4.27g/L and an initial sucrose concentration of 25.44g/L. Results suggest that the proposed methodology can be extended to increase the productivity in terms of metabolite production from this plant cell cultures and other plant species

BIOTEC’98: book of abstracts

IV Iberian Congress on Biotechnology; I Ibero-American Meeting on BiotechnologyFundação para a Ciência e a Tecnologia (FCT

Application of bioprocess-supercritical fluid extraction techniques in the production and recovery of some selected bioproducts

Thesis (PhD (Chemical Engineering))--Cape Peninsula University of Technology, 2020The use of bioproducts in different commercial sectors such as medicine, agriculture, cosmetics, food, and chemical industries motivates the need for easy production and recovery techniques of bioproducts at laboratory and pilot scale. This study aims at the production and recovery of some selected bioproducts using supercritical fluid extraction techniques. Three products are chosen as case studies: these are ethanol, acetoin, and vanillin, since the ease of separation is influenced by the concentration of the product in the broth, these compounds were selected based on their concentration in the fermentation broth, according to literature sources. A standard method was developed in a spectrophotometer for quantifying the targeted product in the broth, while the product recovery studies was carried out using a supercritical fluid extraction pilot plant. Saccharomyces and Bacillus species were chosen for the bioproduction of the selected bioproducts. Experimental design and statistical analysis of results were carried out using response surface methodology (RSM) and artificial neural network (ANN). Studies on each of the selected bioproducts are as justified in the paragraphs below. Bioethanol production has recently become an increasing trend in research, with a focus on increasing its economic viability. Hence, the need to develop a low-cost fermentation medium with minimum redundant nutritional supplements, thereby minimizing the costs associated with nutritional supplements whereby inoculum preparation becomes necessary for ethanol production. Corn steep liquor (CSL) in glucose fermentation by Saccharomyces Type 1 (ST1) strain and Anchor Instant Yeast (AIY), which are low-cost media, are used as replacements for yeast extract (YE). The fermentation process parameters were optimized using artificial neural networks (ANN) and the response surface methodology (RSM). The study shows that for CSL, a maximum average ethanol concentration of 41.92 and 45.16 g/L representing 82% and 88% of the theoretical yield were obtained after 36 h of fermentation in a shake flask for ST1 and AIY respectively. For YE, ethanol concentration equivalent to 86% and 88% of theoretical yield were obtained with ST1 and AIY respectively after 48 h. Although, ANN predicted the responses of ethanol yield better than RSM, optimum conditions for ethanol production were better predicted by RSM. The consumers’ preference for ‘naturally’ produced aromas drives the development of bioproduction of acetoin from glucose with a view to optimize its production. The results revealed that by using a cheap nitrogen source, corn steep liquor, the yield of acetoin was similar to those of yeast and beef extracts. Furthermore, it was shown that by using Box-Behnken design, the optimum parameters such as glucose concentration, corn steep liquor, and inoculum size to maximize the concentration of acetoin produced were 78.40 g/L, 15.00% w/v and 2.70% v/v respectively. The validated concentration of acetoin produced in a triplicate analysis, 10.7 g/L, was 0.06% less than the predicted value. Increasing awareness of consumers of healthy, eco-friendly flavors and fragrances motivates the bioproduction of vanillin. The interactive effects of three variables on vanillin yield were evaluated by response surface methodology (RSM) with Box-Behnken design (BBD) model. The results showed the optimum conditions for the biotransformation of ferulic acid into vanillin can be achieved with maximum overall desirability (D) of 1.0 and a significant (p<0.05) quadratic model with regression coefficient (R2) of 0.995. Corn steep liquor, initial ferulic acid concentration and pH significantly influence the concentration of vanillin in the broth. The results in triplicate experiments confirmed vanillin yield of 386 mg/L after validation, which was in agreement with the prediction of the model. The maximum vanillin yield of 384.40 mg/L was predicted when corn steep liquor, ferulic acid concentration and pH were 7.72 g/L, 2.33 g/L, and 9.34 respectively. Fermentation system in a bioreactor has been proven to be an efficient system for the study of controlled fermentation variables when compared to a shake flask study. The influence of agitation, aeration, time and pH were analysed by Taguchi orthogonal array design for the upscale of acetoin in a bioreactor. The optimized parameters in 1.3L of fermentation vessel were as follows: 300 rpm agitation, 1.5 slpm aeration; 2 days’ fermentation time and 6.5 pH value. Agitation with above 70% was the most contributing factor and other variables were less than 30% in the percentage analysis of variance of each fermentation variables in the batch study of acetoin. A fourfold gain in acetoin titre (42.30 g/L) was obtained with the same substrate concentration in a lab-scale bioreactor on scaling up when compared with the shake flask batch study. The validated acetoin concentration of 41.72 g/L was obtained after a triplicate experiment to confirm the possibility of reproducing acetoin using the optimized conditions. Many separation techniques have been proven to recover value-added products from fermentation broth with a preference for several methods above other and new techniques that are emerging. Supercritical fluids separation using CO2 is one such technique. The feasibility of acetoin concentration and recovery was studied in supercritical CO2 pilot plant with pressure ranges of 100 to 300 bar, CO2 feed rate of 5 to 15 kg/h, at a process temperature of 37 and 80 °C in simulated and fermentation broth, respectively. The validated conditions for the fractionation of acetoin by supercritical fluid extraction (SFE) were determined as follows: extraction pressure, 300 bar; CO2 feed rate, 15 kg/h; extraction temperature 37 °C; and fractionation time of 30 minutes. At these operating conditions, the percentage recovery of acetoin with respect to the feed solution at the raffinate for the simulated and actual ermentation broth was 77.8% (0.20 g/L) and 77% (0.15 g/L) respectively. A two-fold extract increase was obtained after 30 minutes of fractionation. The study provides the technical feasibility and the base case data which are critical to the development and design of processes for production and recovery of acetoin. The lesson gleaned from this study may be extended to develop processes for the production and recovery of other bioproducts (ethanol and vanillin)

Optimization of biomass production and lipid formation from Chlorococcum sp. cultivation on dairy and paper-pulp wastewater.

Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.Abstract available in PDF

Probing herb induced liver injury (HILI) using population data and computational phyto-analysis

Despite the ‘natural’ origin of herbal medicines, they can cause adverse effects such as hepatotoxicity, which has led to regulatory action including market withdrawal. This study aimed to explore herb-hepatotoxicity associations and to identify a common pharmacophore among the phytoconstituents of implicated herbs. Data from the United States adverse event reporting system (AERS) (2004-2011) were analysed retrospectively for herb-hepatotoxicity associations using disproportionality analysis. Chemical constituents in identified hepatotoxic herbs were examined for a common pharmacophore and validated against a set of known hepatotoxic and non-hepatotoxic compounds. Significant herb-liver injury associations (p<0.05) were found for 15 herbs including kava, valerian and black cohosh. Analysis of specific adverse reaction groupings revealed new information: HILI with immune features was significantly associated with seven herbs including kava, evening primrose and valerian. Pharmacophore analysis revealed a 3-point hypothesis with 1 hydrogen bond acceptor, 1 hydrogen bond donor and 1 hydrophobic group that gained a high survival score, high selectivity and high specificity relative to other hypotheses. This hypothesis may be a clue to a common toxicity pathway shared by these herbs. Further research is required to investigate whether a causal relationship exists between the implicated herbs and liver injury and to identify the toxicity mechanisms

Impact of nanobiocatalysts on Saccharomyces cerevisiae metabolism for ethanol production: process optimization, kinetic studies and preliminary scale-up.

Doctoral Degree. University of KwaZulu-Natal, Pietermaritzburg.Abstract available in PDF

Achieving Social and Economic Development Through Ecological and Organic Agricultural Alternatives

The third edition of the continental conference (3AOC) is holding in Nigeria October 5 – 9, 2015 with the theme “Achieving Social and Economic Development Through Ecological and Organic Agricultural Alternatives”. This conference is coming up in the continent when the call for need to improve rural livelihoods of Africans is becoming louder by the day. A veritable tool through which the livelihood of an average African can be improved is Organic Agriculture because it has an inherent potential to reduce production costs regularly incurred by small-medium scale farmers (principal actors in African agriculture), reduce debts, increase income, mitigate the vagaries of climate change, cope with market fluctuations, sustain soil fertility, minimize health hazards etc. It is envisaged that the 3AOC will provide an excellent platform to exchange ideas on the role ecological and organic agricultural alternatives can play in achieving social and economic development in the continent. The 3AOC scientific track is hereby documented as Book of Proceedings

Natural Medicinal Plants

This book, Natural Medicinal Plants is a comprehensive overview of drugs derived from medicinal plants and their use in treating human illnesses such as cancer. Chapters include scientific evidence on flora rich in active ingredients