Process conditions for a rapid in situ transesterification for biodiesel production from oleaginous yeasts

BACKGROUND: Microbial oils produced by diverse microorganisms are being considered as alternative sources of triglycerides for biodiesel production. However, the standalone production of biodiesel from microorganisms is not currently economically feasible. In case of yeasts, the use of low-value nutrient sources in microbial production and the implementation of cost-efficient downstream processes could reduce costs and make microbial lipids competitive with other commodity-type oils in biodiesel production. Industrial biodiesel synthesis from oleaginous seeds is currently based on a multistep process. However, a simple process called in situ transesterification (ISTE), which takes place within the biomass without a previous lipid extraction step, is receiving increasing interest. In this work, the optimal conditions for an ISTE process to obtain biodiesel from previously selected oleaginous yeast (Rhodotorula graminis S1/S2) were defined using the response surface methodology (RSM). RESULTS: Using the RSM approach, the optimal conditions for the maximum yield with minimum reaction time included a methanol-to-biomass ratio of 60:1, 0.4 M H2SO4, and incubation at 70°C for 3 h. The optimized in situ process yield was significantly higher (123%) than that obtained with a two-step method in which fatty acids from saponifiable lipids were first extracted and then esterified with methanol. The composition of the fatty acid methyl ester mixture obtained from R. graminis S1/S2 by ISTE met Uruguayan standards for biodiesel. CONCLUSION: The characteristics achieved by the optimized method make microbial oil a potential alternative for biodiesel production from yeast at an industrial scale.

Evaluación del estado nutricional de yodo en una población de embarazadas / Assessment of iodine nutritional status in a pregnant women population

Introducción: el déficit de yodo en embarazadas puede perjudicar la salud de la madre y del recién nacido, está relacionado con diversas complicaciones obstétricas como abortos espontáneos, muertes fetales, anomalías congénitas, aumento de la mortalidad perinatal y el cretinismo. La Organización Mundial de la Salud (OMS) establece que el déficit de yodo sigue siendo la principal causa global evitable tanto de retraso mental como de parálisis cerebral, y afecta en grado variable el desarrollo y bienestar de millones de personas en el mundo. Las embarazadas constituyen una población vulnerable, con altos requerimientos de yodo. No se han realizado estudios en embarazadas en Uruguay luego de la yodación universal de la sal (1999). Objetivo principal: evaluar el estado nutricional de yodo en una población de embarazadas. Objetivo secundario: obtener una impresión cualitativa de las posibles fuentes de yodo nutricionales en esta población. Material y método: se realizó una encuesta nutricional específicamente confeccionada y se recolectaron muestras de la primera orina de la mañana para determinar yoduria en mujeres embarazadas independientemente del trimestre. Se consideró deficiencia de yodo para esta población una excreción urinaria media por debajo de 150 ?g/l (OMS, 2007). Resultados: se analizaron 96 muestras de orina. La mediana de la excreción urinaria media de yodo para esta población fue de 182 ?g/l, considerándose en rango de normalidad para las embarazadas valores entre 150 y 249 ?g/l. Conclusiones: este estudio ha confirmado que la excreción urinaria de yodo en la orina está en el rango adecuado a lo establecido por la OMS.

Abstract Introduction: iodine deficit in pregnant women may have a negative effect on the mother and the newborn, and it is associated to several obstetric complications such as spontaneous abortion, fetal death, congenital anomalies, increase of perinatal mortality and cretinism. The World Health Organization (WHO) establishes that iodine deficit is still the main global avoidable cause for mental retardation and brain palsy, and it affects the development and wellbeing of millions of people around the world at different levels. Pregnant women are a vulnerable population with high requirements. No studies in the pregnant women population have been conducted in Uruguay after the universal salt iodation in 1999. Main objective: assessment of iodine nutritional condition in a pregnant women population Secondary objective: to obtain a qualitative impression of the possible sources of nutritional iodine in this population. Methods: a specially prepared nutritional survey was conducted and first morning urine samples were collected to determine ioduria in pregnant women, regardless of the trimester. In this population, iodine deficiency was defined for this population when urine excretion was below 150 ?g/l (WHO, 2007). Results: ninety six urine samples were analysed. Median of the average urinary excretion for this population was 182 ?g/l, normal rates being between 150 and 249 ?g/l. Conclusions: the study confirmed iodine urinary excretion lies within the adequate range established by the WHO.

Resumo Introdução: a deficiência de iodo em gestantes pode prejudicar a saúde da mãe e do recém-nascido e está relacionado com diversas complicações obstétricas como abortos espontâneos, mortes fetais, anomalias congénitas, aumento da mortalidade perinatal e também com o cretinismo. A Organização Mundial da Saúde (OMS) declarou que a deficiência de iodo continua sendo a principal causa global evitável tanto de retraso mental como de paralisia cerebral, e que afeta, em diferentes graus, o desenvolvimento e o bem-estar de milhões de pessoas no mundo. As gestantes são uma população vulnerável com altos requerimentos. No Uruguay, desde 1999 quando começou a iodetação universal do sal, não são realizados estudos em gestantes. Objetivo principal: avaliar o estado nutricional de iodo em uma população de gestantes. Objetivo secundário: obter uma relação qualitativa das possíveis fontes nutricionais de iodo nesta população. Material e métodos: realizou-se um inquérito nutricional e foram coletadas amostras da primeira urina da manhã para determinar iodúria em gestantes em qualquer trimestre da gravidez. Nesta população considerou-se deficiência de iodo uma excreção urinaria média inferior a 150 ?g/l (OMS, 2007). Resultados: foram analisadas 96 amostras de urina. A mediana da excreção urinaria media de iodo nesta população foi de 182 ?g/l, considerando como normais valores entre 150 e 249 ?g/l. Conclusões: este estudo confirmou que a excreção urinaria de iodo está compreendida no intervalo considerado adequado de acordo com o estabelecido pela OMS.