study on the effect of levulinic acid on whey-based biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by hydrogenophaga pseudoflava
نویسندگان
چکیده
background and objective: production of polyhydroxyalkanoate copolyesters consisting of 3-hydroxybutyrate and 3-hydroxyvalerate units was for the first time studied using the production strain hydrogenophaga pseudoflava based on sustainable raw materials. this strategy provides for increased cost efficiency in pha production and in enhanced material quality. material and methods: as a particularity, production of these poly(3-hydroxybutyrate-co-3- hydroxyvalerate) copolyesters was based on a novel substrate/co-substrate combination: whey permeate from dairy industry, on the one hand, acted as substrate for biomass and 3hb biosynthesis; on the other hand, levulinic acid, accessible from various renewable resources, was used as 3hv-related precursor compound. the experiments were carried out on shaking flask scale using defined nutrient media. results and conclusion: applied during nutritionally balanced growth of h. pseudoflava, levulinicacid displays drastic growth inhibition at rather low concentrations of 0.2 g l-1 (growth inhibition constant ki = 0.032), which suggests the careful supply of this compound in the first phase of cultivation. under nitrogen-free cultivation conditions, inhibition of the strain´s metabolism by levulinic acid was less pronounced. here, poly(3-hydroxybutyrate-co- 3-hydroxyvalerate) concentrations up to 4.2 g l-1 and volumetric poly(3-hydroxybutyrate-co-3- hydroxyvalerate) productivities up to 0.06 g l-1 h -1 were achieved in dependence on the precursor supply. investigating poly(3-hydroxybutyrate-co-3-hydroxyvalerate) composition in setups supplied with differently composed whey/levulinic acid mixtures revealed 3- hydroxyvalerate fractions in the polymer between 0 and 0.6 mol mol-1 . this study successfully demonstrates the feasibility of combined utilization of different waste- and by-products from food industry and agriculture for generation of value-added 2nd generation biopolymers. conflict of interest: the authors declare no conflict of interest.
منابع مشابه
Biosynthesis and local sequence specific degradation of poly(3-hydroxyvalerate-co-4-hydroxybutyrate) in Hydrogenophaga pseudoflava.
A novel copolymer that consisted of 3-hydroxyvalerate and 4-hydroxybutyrate, P(3HV-co-4HB), was synthesized in Hydrogenophaga pseudoflava by growing it in media containing gamma-valerolactone and gamma-butyrolactone as a carbon source. The monomer ratio in the copolymer was changed by altering the feed ratio of the two lactones. The cultivation technique was composed of three steps: the first-s...
متن کاملthe effect of consciousness raising (c-r) on the reduction of translational errors: a case study
در دوره های آموزش ترجمه استادان بیشتر سعی دارند دانشجویان را با انواع متون آشنا سازند، درحالی که کمتر به خطاهای مکرر آنان در متن ترجمه شده می پردازند. اهمیت تحقیق حاضر مبنی بر ارتکاب مکرر خطاهای ترجمانی حتی بعد از گذراندن دوره های تخصصی ترجمه از سوی دانشجویان است. هدف از آن تاکید بر خطاهای رایج میان دانشجویان مترجمی و کاهش این خطاها با افزایش آگاهی و هوشیاری دانشجویان از بروز آنها است.از آنجا ک...
15 صفحه اولthe effect of traffic density on the accident externality from driving the case study of tehran
در این پژوهش به بررسی اثر افزایش ترافیک بر روی تعداد تصادفات پرداخته شده است. به این منظور 30 تقاطع در شهر تهران بطور تصادفی انتخاب گردید و تعداد تصادفات ماهیانه در این تقاطعات در طول سالهای 89-90 از سازمان کنترل ترافیک شهر تهران استخراج گردید و با استفاده از مدل داده های تابلویی و نرم افزار eviews مدل خطی و درجه دوم تخمین زده شد و در نهایت این نتیجه حاصل شد که تقاطعات پر ترافیک تر تعداد تصادفا...
15 صفحه اولthe effect of genre-based teaching on reading comprehension of literary texts
تحقیق حاضر به بررسی کاربرد روش ژانر-محور را در محیط آموزش زبان عمومی می پردازد.روش ژانر-محور به زبان آموزان کمک میکند که در زمینه خوانش پیشرفت کنند. بعضی از محققین معتقد اند که روش تدریس ژانر-محور به تدریج به زبان آموزان کمک می کند تا در درک ژانر های مختلف مهارت یابند (هایلند 2004).همچنین امروزه توجه روز افزونی به اهمیت استفاده از ادبیات در برنامه آموزشی زبان انگلیسی (esl/efl ) شده است. زمانی ک...
15 صفحه اولthe role of task-based techniques on the acquisition of english language structures by the intermediate efl students
this study examines the effetivenss of task-based activities in helping students learn english language structures for a better communication. initially, a michigan test was administered to the two groups of 52 students majoring in english at the allameh ghotb -e- ravandi university to ensure their homogeneity. the students scores on the grammar part of this test were also regarded as their pre...
15 صفحه اولمنابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
applied food biotechnologyجلد ۴، شماره ۲، صفحات ۱-۱۰
میزبانی شده توسط پلتفرم ابری doprax.com
copyright © 2015-2023