An overview of biotechnological production of propionic acid: from upstream to downstream processes

The increasing demand for propionic acid (PA) production and its wide applications in several industries, especially the food industry (as a preservative and satiety inducer), have led to studies on the low-cost biosynthesis of this acid. This paper gives an overview of the biotechnological aspects of PA production and introduces Propionibacterium as the most popular organism for PA production. Moreover, all process variables influencing the production yield, different simple and complex carbon sources, the metabolic pathway of production, engineered mutants with increased productivity, and modified tolerance against high concentrations of acid have been described. Furthermore, possible methods of extraction and analysis of this organic acid, several applied bioreactors, and different culture systems and substrates are introduced. It can be concluded that maximum biomass and PA production may be achieved using metabolically engineered microorganisms and analyzing the most significant factors influencing yield. To date, the maximum reported yield for PA production is 0.973 g·g-1, obtained from Propionibacterium acidipropionici in a three-electrode amperometric culture system in medium containing 0.4 mM cobalt sepulchrate. In addition, the best promising substrate for PA bioproduction may be achieved using glycerol as a carbon source in an extractive continuous fermentation. Simultaneous production of PA and vitamin B12 is suggested, and finally, the limitations of and strategies for competitive microbial production with respect to chemical process from an economical point of view are proposed and presented. Finally, some future trends for bioproduction of PA are suggested.

Effect of Process Variables on Survival of Bacteria in Probiotics Enriched Pomegranate Juice.

Aims: The consumption of foods and beverages containing probiotic microorganisms is a growing, global consumer trend. In this research, production of probiotic pomegranate juice containing Lactobacillus plantarum and Lactobacillus delbrueckii was studied. Study Design: Plackett-Burman statistical design was used to evaluate the impact of eleven process variables on the viability of both probiotics. Impact of incorporation of grape juice, tomato juice and pomegranate peel extract as well as phenolic compounds and vitamins have been investigated. Place and Duration of Study: Department of Food Science and Technology, Varamin Branch, Islamic Azad University, Varamin, Tehran, Iran, between Sep 2012 and July 2013. Methodology: Pomegranate juices were inoculated with probiotic bacteria and their survival was evaluated every week by pure plate method. The effect of 11 variables (in two levels) on survival of bacteria by the statistical design of Plackett-Burman was evaluated. For this purpose, 12 treatments in triplicate by the Minitab (version = 11.0) software at significant levels α= .01 were analyzed. Results: The highest survival rate of L. plantarum (4.74 ×106 CFU/mL) and L. delbrueckii (4 ×106 CFU/mL) was obtained by 10% v/v inoculation of a 48 h inoculum culture in MRS broth medium to enriched pomegranate juice (10% v/v Grape juice, 5% v/v tomato juice, 0.1% v/v pomegranate peel extract and 2.0 g.L glucose) which was inoculated in anaerobic condition for 72 h at 37ºC and kept for 2 weeks at environment temperature. Sensory evaluation shows the probiotic juice was accepted by consumers with no significant difference in comparison to control in terms of taste, odour and overall acceptability (P>.05). Conclusion: The results of this study suggest that grape, tomato juices and pomegranate peel extract exert a protective effect on L. plantarum and L. delbrueckii viability under acidic condition of pomegranate juice and storage time, which was associated with the chemical composition of them. This study indicates that develop of probiotic pomegranate juices with acceptable viability and stability of the probiotic is possible.

Algunas dimensiones relacionadas con el rendimiento académico de estudiantes de Administración y Dirección de Empresas / Some Aspects of the Business Administration Students Academic Performance

En esta investigación se analiza el efecto de distintas variables sobre el rendimiento académico. Para esto se toma como referencia el modelo 3P (presagio-proceso-producto). El estudio empírico se desarrolla con alumnos universitarios. Los resultados indican que el rendimiento conceptual difiere significativamente del rendimiento procedimental. Se constata que la capacidad explicativa de las variables de presagio resulta superior a las variables de proceso, tanto en el rendimiento conceptual como en el procedimental. Además, el estilo cognitivo, el género y la asistencia resultan factores determinantes del rendimiento académico en todas sus dimensiones. Así, los estudiantes más analíticos, varones y con alto nivel de asistencia obtienen mejores resultados. En el rendimiento procedimental y global afecta también la motivación y el autoconcepto académico.

The goal is to analyze the determinant factors of each of the academic performance dimensions. The theoretical foundation is the 3P model (presage, process, and product). The empirical analysis is developed with students of Business administration in their last academic year. The results show that the conceptual performance is difference from the procedural performance and that such difference is statistically significant. The presage variables are more relevant that the process variables explaining either the conceptual performance or the procedural performance. Furthermore, the cognitive style, the gender and class attendance are explanatory factors of the academic performance in all the three dimensions. Male students with higher analytic capabilities and high attendance are the ones with higher performance. Student motivation and academic self-concept are variables that contribute to explain procedural and global performance.

The Effects of Emotionally Focused Therapy(EFT) for Couples : Pilot Study / 신경정신의학

OBJECTIVES: This study investigated the effects of Emotionally Focused Therapy (EFT) on distressed married couples. METHODS: We conducted 5 to 19 EFT sessions once a week with 10 couples from Yongin Mental Hospital who were experiencing marital conflict. We assessed participants before and after EFT, using the Beck Depression Inventory (BDI), Symptom Checklist 90-R (SCL-90R), and Korean Marital Satisfaction Inventory (K-MSI). The EFT consisted of 3 stages comprising 9 steps. Every couple followed this EFT structure. RESULTS: After completing the EFT sessions, the inventories showed the couples experiencing significant improvements in various psychological symptoms and marital satisfactions. CONCLUSION: These results indicate that EFT could be applied to distressed couples in a clinical setting and could effectively reduce psychological symptoms and improve marital satisfaction. Further study of the generalizability of these results and of the process variables are needed.