Production of the Enzyme Cyclodextrin Glycosyltransferase Using Different Fermentation Techniques

Cyclodextrins produced by cyclodextrin glycosyltransferase (CGTase) are widely used in the pharmaceutical industry to improve the solubility of drug substances as well as protect them against oxidation. The use of this enzyme in the cosmetics industry is also significant. CGTase is an enzyme that belongs to the α-amylase family, which is part of the group of non-Leloir glycosyltransferases. Enzyme-catalysed transglycosylation reactions may involve cyclization, coupling and disproportionation processes. The enzyme CGTase is mostly used to produce cyclodextrins (CDs). CGTase can produce α-, β- and γ-CDs during transglycosylation reactions, depending on the number of glucopyranose units involved (6, 7 or 8). The enzyme CGTase can also be used for enzymatic bioconversion, e.g., in the development of alternative sweeteners, where the bitter aftertaste of the product is reduced during the enzymatic bioconversion of steviol glycosides, thereby obtaining an even sweeter and more advantageous material. In our research, the enzyme CGTase was produced using different fermentation techniques to compare the activity and amount of CGTase produced by each process and optimize the subsequently planned scale-up. In our studies, the strain DSM 13 of Bacillus licheniformis was used, which produced CGTase extracellularly. During the experiments the batch, fed-batch and semi-continuous fermentation techniques were compared in terms of enzymatic production. All cultivation processes were carried out in a desktop lab scale fermenter

Investigations into Enzymatic Bioconversion to Form Rebaudioside A from Stevioside

Stevia rebaudiana Bertoni is a perennial shrub from South America that produces steviol glycosides which are 200-300 times sweeter than sugar. Stevioside and rebaudioside A are the main sweetening components of its leaves. Steviol glycosides are diterpenoids whose biosynthetic pathways have four steps in common with gibberellic acid formation. The most important enzyme in the biosynthetic pathway expressed by the gene UGT76G1 is referred to as UDP-glycosyltransferase 76G1. It converts stevioside into rebaudioside A. The former has a bitter aftertaste and is a poorer sweetener but is most abundant. This enzyme can be produced in a next generation recombinant way by Escherichia coli and Saccharomyces cerevisiae. Trichoderma longibrachiatum produces the enzyme β-1,3-glucanase enzyme, which can perform a transglycosylation between stevioside to gain rebaudioside A. In our study, a full-factorial statistical experimental design that applies different glycosyl donors, temperatures, enzyme-to-substrate ratios and pH's as factors in order to achieve higher Reb A ratios in S. rebaudiana extracts after transglycosylation is reported. The presented statistical design was appropriate to indicate relevant and significant factors, providing a good basis for an upcoming experimental design of a real-world optimization

Modeling the Biosurfactant Fermentation by Geobacillus stearothermophilus DSM2313

Biosurfactants are emerging molecules in the 21st century. However, their production intensification is still required for the development of feasible bioprocesses. Therefore, this paper studies a new biosurfactant-producer, namely Geobacillus stearothermophilus DSM2313 during statistical optimization via response surface methodology. After the statistical analysis the optimal pH = 7, glucose = 50 g/L and NH4NO3 = 2 g/L concentrations were determined. The biosurfactant production of the bacteria was predicted by our developed artificial neural network. The optimal harvesting time of the broth and the emulsification index values can be predicted simultaneously with the constructed artificial neural network. The best experiment was also kinetically described, and kinetic constants observed. Surface tension and emulsification activity were measured to characterize the formed products' efficiency. Based on these results, biosurfactants from Geobacillus stearothermophilus DSM2313 can act as bioemulsifier and can be applied for example in microbial enhanced oil recovery

PERCEPCIJA STARENJA U MAĐARSKOJ

Like in many developed countries, the ageing tendency of the population is typical also for the Hungarian age structure, which requires greater attention of the society in the economic, social and health aspects, furthermore, it causes changes in cooperation of generations and their habits and norms. It is related among others to social mobility and the fragmentation of family relationships, which may mean the separation of the older generation from the younger one, therefore children do not get to know older people’s lives or only just a few patterns of those, and they lack coexistence and cooperation opportunities. This situation is influenced by nowadays’ trends (for example anti-ageing), social impacts and expectations associated with the natural ageing process; developing a negative image of ageing in many (especially young) people. For these reasons the study seeks associations with ageing and age-determination in respect of generations to recognise how positive or negative their points of view or feelings are, and how they influence their everyday lives. The results were obtained by using four evaluation methods: personal and online researches, taking of nationally representative samples, organising three focus group discussions, and interviewing master’s students. The results show that the Hungarian respondents have preferably negative opinions about the ageing-related terms. This aspect may have a negative influence on the attitudes of the generations about their subjective value judgment regarding themselves, their age and life situation.Kao i u mnogim razvijenim zemljama, tako je tendencija starenja stanovništva tipična i za mađarsku dobnu strukturu, što zahtijeva veću pažnju društva u ekonomskom, socijalnom i zdravstvenom aspektu; štoviše, ovo uzrokuje promjene u suradnji generacija i njihovim navikama i normama. Između ostalog, ono je povezano i sa socijalnom mobilnošću i fragmentacijom obiteljskih odnosa, što može značiti odvajanje starije generacije od mlađe, i stoga djeca nemaju priliku upoznati živote starijih osoba ili upoznaju samo nekoliko obrazaca življenja, te su uskraćeni za mogućnosti suživota i suradnje. Na ovu situaciju utječu današnji trendovi (npr. anti-aging), socijalni utjecaji i očekivanja povezana s prirodnim procesom starenja uz razvijanje negativne slike starenja kod mnogih (posebno mladih) ljudi. Iz tih razloga, studijom se istražuju asocijacije na starenje i dob s obzirom na generacije, a kako bi se utvrdilo koliko su njihova gledišta ili osjećaji pozitivni ili negativni i kako utječu na njihov svakodnevni život. Rezultati su prikupljeni korištenjem četiri metode: primjenom osobnog i online ispitivanja, koji su provedeni na nacionalno reprezentativnim uzorcima, te provedbom tri fokus grupe i intervjuiranjem studenata. Rezultati pokazuju da mađarski ispitanici imaju negativna mišljenja o pojmovima koji se vežu uz starenje. Ovaj aspekt može negativno utjecati na stavove generacija koji se odnose na njihovu subjektivnu vrijednosnu prosudbu o sebi, njihovu dob i životnu situaciju

Screening for the Heterotrophic Cultivation of Chlorella sorokiniana Using an Indirect Impedance Microbiological Technique

Heterotrophic culturing of microalgae is of great interest as it has the potential to produce feedstock for added-value bioproducts. The general expectation is to develop a method that can help screen for different media compositions and batch fermentation settings more easily and faster. In the current study, an indirect impedance microbiological technique was used to test the effects of various carbon and nitrogen sources on the growth of Chlorella sorokiniana. It was found that this technique has great potential to screen for heterotrophic cultivation conditions of microalgae as the metabolic rate of microorganisms can be determined by measuring the amount of CO2 produced. The BacTrac 4100® was proven to be a suitable instrument to compare several different small-scale culturing settings. Considering the relative changes in impedance observed, the initial cell cumber exhibits an inverse linear correlation with the detection time. Chlorella sorokiniana exhibited an enhanced degree of growth on yeast extract and tryptone, and preferred glucose over acetate or glycerol. An optimum rate of growth at a glucose concentration of 20 gL-1 was also determined. Our novel approach in the field of heterotrophic cultivation of microalgae envisages great prospects for the method in terms of the design of experiments in the field of media optimization

Agrárpiaci Jelentések ÉLŐÁLLAT ÉS HÚS

Az AKI PÁIR adatai szerint a hazai termelésű vágósertés termelői ára áfa és szállítási költség nélkül 506 forint/kilogramm hasított meleg súly volt 2021 májusában, ami 6 százalékos csökkenést jelentett az egy évvel korábbi átlagárhoz képest. A darabolt sertéshús (karaj, tarja, comb) feldolgozói értékesítési ára 7,6 százalékkal volt maga-sabb 2021 májusában 2020 azonos hónapjához képest. ---------- According to AKI PÁIR, the producer price of domestically produced slaughter pigs (excluding VAT and transport costs) was HUF 506/kilogram carcass weight in May 2021, which was 6 per cent decrease compared to the average price in May 2020. The processing sales price of cut pork (loin, ribs, thighs) increased by 7.6 per cent in May 2021 compared to the same month in 2020