Highlight on the problems generated by p-coumaric acid analysis in fermentations

p-Coumaric acid is a natural hydroxycinnamic acid existing in grapes and wine. It is the precursor of the 4-ethylphenol molecule through the bioconversion reaction by Brettanomyces yeast. Chromatographic methods are the most common techniques to detect p-coumaric acid. It is known that this acid is highly unstable in analysis and fermentation experiments. This paper highlights the problems occurring in p-coumaric acid analysis in wine fermentation conditions when studying its bioconversion. First, it was shown that p-coumaric acid was unstable at elevated temperature. On the other hand, it was found that in our experimental conditions p-coumaric acid reacted with ethanol. This work revealed also that the p-coumaric acid is partially adsorbed on Brettanomyces yeast, certainly on cell walls. Because of these phenomena the quantity of p-coumaric acid which can participate to the bioconversion into ethylphenol decreases

Bioconversion de l'acide p-coumarique par Brettanomyces bruxellensis : étude de la cinétique et analyse des étapes réactionnelles

Ce travail étudie la bioconversion de l'acide p-coumarique en 4-éthylphénol par une souche de Brettanomyces bruxellensis, levure de contamination des vins. Deux méthodes analytiques (HPLC/UV et GC/MS) ont été optimisées pour suivre la cinétique de la réaction. L'acide p-coumarique présente un problème de quantification. Son instabilité aux températures élevées et son estérification avec l'éthanol du vin ont été montrées, ainsi que son adsorption sur les parois des levures. L'étude du bilan matière de la bioconversion montre plusieurs étapes réactionnelles. La bioconversion en 4-éthylphénol apparait comme unique voie d'utilisation de l'acide p-coumarique par la souche testée. Le mode d'agitation, la phase de croissance, le taux de la population levurienne, ainsi que la présence de phénols volatils ont montré un effet direct sur la vitesse de la réaction. Enfin, l'adsorption de l'acide p-coumarique sur le PVPP a été présentée comme un moyen de lutte contre l'apparition du 4-éthylphénol dans les vins. ABSTRACT : The aim of this work was the study of p-coumaric acid bioconversion into 4-ethylphenol by Brettanomyces bruxellensis as a contamination yeast of wine. An HPLC/UV and a GC/MS method were optimised to follow up the reaction kinetics. P-coumaric acid presents many quantification problems, and it was shown to be instable at high temperature. Its esterification with wine éthanol as well as its adsorption on yeast cell walls were demonstrated. The study of biosynthesis material balance showed several steps of reaction. The conversion into 4-ethylphenol seems to be the only pathway of p-coumaric acid to be used by Brettanomyces stain tested. The agitation, the growth phase, the yeast population concentration, as well as the presence of volatile phenols have shown a direct effect on reactions rate. Finally, p-coumaric acid adsorption on PVPP was presented as a usefull method to prevent 4-ethylphenol occurrence in win

Analysis of the effectiveness of a cereal milling by product monocomponent medium for the low cost production of Bacillus thuringiensis

Bacillus thuringiensis is a facultative anaerobe, gram positive, spore forming bacterium. The biotechnological importance of this bacterium resides in its ability to produce, during sporulation, crystal proteins known as delta-endotoxins which express specific insecticidal activity. At industrial scale, the culture media represents an important part of B. thuringiensis based biopesticides production cost. According to the literature, different agro-industrial residues and byproducts were used as sources of proteins in order to reduce the cost of B. thuringiensis culture medium, but carbohydrates (glucose, starch or molasses) and/or mineral sources were added. In this work, a cereal milling by-product (CMB) as a monocomponent medium was investigated and compared to synthetic mediums in terms of delta-endotoxin yield and productivity in submerged fermentation of different strains of B. thuringiensis. The CMB was shown efficient to be used as a complete substrate (source of proteins, carbohydrates and minerals) for B. thuringiensis production. The optimal CMB ratio in the culture medium was found to be 6% in shake flasks experiments. The consumption of the CMB sugars by the bacteria was analyzed. Production of the bio-insecticide in lab-bioreactor in controlled conditions was equally performed to give basic elements for extrapolation in industrial conditions

Health Care Waste generation rates and patterns: The case of Lebanon

The objective of this study is to analyze Infectious Health Care Waste generation rates and patterns in Lebanon. Therefore, the quantities generated during five years by 57 hospitals from a total of 163 in the country have been analyzed. The seasonal evolution of Infectious Health Care Waste production and the evolution of the evaluation of the trends over years have been studied. Besides, the generation per capita have been estimated and compared to other countries. The variance between categories and the correlation between number of beds and Infectious Health Care Waste generation have been analyzed. The obtained results showed that the large private hospitals (over 200 beds) are characterized by their high generation rate: an average of 2.45 kg per occupied bed^-1 day^-1, whereas the average generation rate for other categories is 0.94 kg per occupied bed^-1 day^-1. The weighted mean is 1.14 per occupied kg bed^-1 day^-1. Small public hospitals (i.e. less than 100 beds) have the smallest standard deviation: 0.13, whereas large private hospitals (i.e. over than 200 beds) have the highest standard deviation: 0.40. Infectious Health Care Waste generation has been estimated to 1.42 kg/capita/year. The correlation between the numbers of hospitals beds in hospitals and the generation rate per bed is weak. The correlation between Infectious Health Care Waste generation per day and beds number is stronger. The total quantity produced by hospitals has increased over the five past years. These results suggest that the quantities of medical waste are not well controlled, and that hospitals have a defective monitoring management system of their waste. Annual peaks are observed in June, July, and December. Thus, this study, for the first time in Lebanon, has provided information on the infectious waste generation, allowing benchmarking between hospitals and between countrie

Influence de l'étape de croissance et de la quantité de brettanomyces bruxellensis sur la production d'éthyl-phenols

Influence de l'étape de croissance et de la quantité de brettanomyces bruxellensis sur la production d'éthyl-phenol

Indicators of Sustainable Development for Health Care Waste Treatment Industry

Sustainable development is more and more considered as a key parameter and a driving strategy for sustainable performance. Today, numerous organizations develop their own performance indicators as no standard set of performance indicators could be generalized as meaningful in terms of sustainability performance. Particularly, the context of developing countries, where the concept of sustainability is not well diffused yet and where economic difficulties and constraints result most of the times in underestimation of environmental and social considerations, requires specifically adapted indicators. Specially, the sector of health care waste management lacks of sustainability indicators. This sector ensures the treatment, before disposal, of hazardous health care waste generated by health care centers (hospitals, clinics, and others). The evaluation system is designed for monitoring the pace of gaining sustainability within this sector. The objective of this article is to propose a sustainability evaluation system adapted to the needs and situation of developing countries, based on meaningful, practical, easily measurable and applicable indicators for the Infectious Health Care Waste (IHCW) Treatment sector

Evaluation of a cereal milling by-product for the low cost production of Bacillus thuringiensis kurstaki in submerged fermentation

With the idea of finding a cheap medium for the mass production of Bacillus thuringiensis (Bt), a cereal milling by product (CMB) was evaluated and was shown efficient to be used as a source of carbohydrates, proteins and minerals for the production of δ-endotoxins in submerged fermentation of a new strain of Bacillus thuringiensis kurstaki “Lip”. The results obtained in 1000 mL shake flasks experiments showed that the toxin proteins concentration produced in the 6% (w/v) CMB medium was 2.4 fold and 1.54 fold greater than the values reached in the Anderson medium and in a standard semi synthetic medium respectively, while there was no significant difference between the cell, spore and crystal counts or between the protein profiles of the “Lip” spore/crystal complex obtained in the three mediums. Considering all three factors, relative yield, productivity and cost, the use of the CMB mono-component medium was proved much more economical for an industrial production of “Lip” than the references mediums. Moreover, the suitability of the medium for large scale production of Bt based bio insecticide was evidenced in a 5 L lab bioreactor

The creation and monitoring of a network for solid healthcare waste management

Healthcare waste mismanagement constitutes a serious environmental and sanitary problem, especially in developing countries. This article describes the strategy and the methodology of the implementation of a national network for healthcare waste management by a non-profit organisation in Lebanon, taking into consideration environmental, social and economic issues. It presents a holistic description of the main aspects of this crucial sustainable development topic: the elaboration of the strategy and the selection of the optimal treatment technique based on an analysis of the context; the training on waste minimisation and waste management issues inside hospitals; the waste transportation and treatment procedures; the quality management of the process; the evaluation and the monitoring of the produced quantities and the established system; the optimisation of sterilisation parameters and process in order to reduce sterilisation time and fuel consumption

The effect of aeration conditions, characterized by the volumetric mass transfer coefficient KLa, on the fermentation kinetics of Bacillus thuringiensis kurstaki

The aeration is a key factor for Bacillus thuringiensis growth, sporulation and δ-endotoxins production. The objective of our work was to study the effect of aeration on the fermentation kinetics of Bacillus thuringiensis kurstaki (Btk), cultivated in a cereal milling byproduct (CMB) mono-component medium, in order to improve the δ-endotoxins productivity. Aeration conditions were systematically characterized by the volumetric mass transfer coefficient KLa. In the 6% CMB culture medium, different values of the maximal specific oxygen uptake rate were obtained at different values of KLa. For KLa of 7.2 h−1, the growth was inhibited and the sporulation was defective. There was a linear increase of the average specific growth rate and faster sporulation and liberation of spores and δ-endotoxins crystals when KLa was increased between 13.3 h−1 and 65.5 h−1. Similar kinetic was observed in cultures performed at KLa equal to 65.5 h−1 and 106.2 h−1. The highest toxins productivity of 96.1 mg L−1 h−1 was obtained in the 9% CMB culture medium for KLa of 102 h−1. It was possible to track the evolution of the bacterial cells between vegetative growth, sporulation and liberation of mature spores by following the variation of the CO2 percent in the effluent gas

Comparison of steam sterilization conditions efficiency in the treatment of Infectious Health Care Waste

Many studies show that the treatment of Infectious Health Care Waste (IHCW) in steam sterilization devices at usual operating standards does not allow for proper treatment of Infectious Health Care Waste (IHCW). Including a grinding component before sterilization allows better waste sterilization, but any hard metal object in the waste can damage the shredder. The first objective of the study is to verify that efficient IHCW treatment can occur at standard operating parameters defined by the contact time–temperature couple in steam treatment systems without a pre-mixing/fragmenting or pre-shredding step. The second objective is to establish scientifically whether the standard operation conditions for a steam treatment system including a step of pre-mixing/fragmenting were sufficient to destroy the bacterial spores in IHCW known to be the most difficult to treat. Results show that for efficient sterilization of dialysis cartridges in a pilot 60L steam treatment system, the process would require more than 20 min at 144 °C without a pre-mixing/fragmenting step. In a 720L steam treatment system including pre-mixing/fragmenting paddles, only 10 min at 144 °C are required to sterilize IHCW proved to be sterilization challenges such as dialysis cartridges and diapers in normal conditions of rolling