A Model for Converting Solid State Fermentation Growth Profiles Between Absolute and Relative Measurement Bases

A mathematical model is developed for converting between the two measurement bases commonly used in the construction of growth profiles in solid-state fermentation, namely absolute mass ratio m(dry biomass)/m(initial dry matter) and relative mass ratio m(dry biomass)/m(dry matter). These are not equivalent, due to the loss of dry matter as CO2 during the fermentation. The model is equally applicable to any biomass component used in indirect measurements of growth, such as protein. Use of the model to convert absolute mass ratio of the biomass profiles for the growth of Rhizopus oligosporus to a relative basis gave profiles that agreed well with the experimentally determined relative biomass profiles. This agreement was obtained for three different fermentations using the same set of parameter values in the model, namely a yield coefficient of m(protein)/m(dry substrate) = 0.2 g/g and a maintenance coefficient of zero, giving confidence in the reliability of the model. The model was then used to show that the measurement basis used can affect the form of the curve and therefore can also affect the conclusion drawn about the type of kinetics shown by the organism, with the extent of this effect depending on the length of time that growth occurs and the values of the yield and maintenance coefficients. This work shows that great care must be taken in drawing conclusions about growth kinetics in solid-state fermentation

Amido de milho pré-gelatinizado por extrusão : estudo das variáveis de processo e do efeito da adição de emulsificantes

Orientador: Prof. Dr. Moacir KaminskiDissertaçao (mestrado) -Universidade Federal do Paraná, Setor de Tecnologia, Curso de Pós-Graduação em Tecnologia QuímicaInclui referências: p. 184-196Resumo: O presente trabalho estuda o efeito das variáveis da extrusão - umidade da matéria-prima, diâmetro da matriz, temperatura - nas propriedades físicas do amido de milho extrusado, bem como, a influência da adição de emulsificantes nas qualidades funcionais deste produto. O emprego da metodologia da superfície de resposta possibilitou a obtenção das equações empíricas que correlacionaram as variáveis estudadas com as respostas obtidas. As variáveis temperatura, seguida da umidade, revelaram-se como mais significativas nas propriedades do amido extrusado. Na região experimental abordada, o diâmetro da matriz não atuou significativamente nas propriedades de pasta, nos índices de absorção e solubilidade em água. A adição de monoglicerídeos destilados e estearoil-2-lactillactato de sódio e de cálcio nos níveis de 0,5% e 1,0%, geralmente promoveu acréscimo na viscosidade inicial das amostras, e reduziu os efeitos da retrogradação dos géis amido, com exceção do CSL, que causou um aumento na sinerese

Primjena proizvoda dobivenog fermentacijom, koji sadrži lipaze iz Rhizopus microsporus, u hidrolizi otpadnih voda mliječne industrije s velikim udjelom masnoća

The filamentous fungus Rhizopus microsporus CPQBA 312-07 DRM was grown in solid-state cultivation and the fermented solid produced was used to hydrolyze triacylglycerols in a high-fat dairy wastewater. For the solid-state cultivation, a mixture of sunflower seed meal and sugarcane bagasse (1:3 by mass on dry basis) was selected. After 18 h of culture, the fermented product had an activity, measured titrimetrically against triolein, of 26 U per gram of dry solids. This substrate mixture does not suffer from compaction and therefore can be used in large scale solid-state cultivation bioreactors. When used to pretreat a high-fat dairy wastewater, with an oil and grease level above 1300 mg/L, the fermented solid reduced the oil and grease level to below 300 mg/L after 72 h at 35 °C. Further work is required to improve the production of lipolytic activity in the solid-state cultivation step and to find the optimum pretreatment time in the wastewater pretreatment step.Uzgojem filamentozne plijesni Rhizopus microsporus CPQBA 312-07 DRM na čvrstoj podlozi dobiven je fermentirani proizvod koji se može upotrijebiti za hidrolizu triacilglicerola iz otpadnih voda mliječne industrije s velikim udjelom masnoća. Kao podloga za uzgoj upotrijebljena je smjesa suncokretove sačme i otpadaka šećerne trske u omjeru od 1:3, na bazi suhe tvari. Nakon 18 sati uzgoja dobiveni je proizvod imao aktivnost od 26 U/g suhe tvari, mjerenu titracijom pomoću trioleina. Utvrđeno je da se podloga može koristiti u bioreaktorima većeg volumena, a da dobiveni proizvod smanjuje udio masti i ulja u otpadnim vodama mliječne industrije s velikim udjelom masnoća (preko 1300 mg/L) čak za 300 mg/L nakon 72 sata fermentacije pri 35 °C. Postupak treba podrobnije ispitati kako bi se postigla veća lipolitička aktivnost i utvrdilo optimalno vrijeme prethodne obrade otpadnih voda

Procjena produktivnosti bioreaktora Zymotis sa čvrstim slojem zasnovana na ukupnom volumenu reaktora

In this work a method of analyzing the performance of solid-state fermentation bioreactors is described. The method is used to investigate the optimal value for the spacing between the cooling plates of the Zymotis bioreactor, using simulated fermentation data supplied by a mathematical model. The Zymotis bioreactor has good potential for those solid-state fermentation processes in which the substrate bed must remain static. The current work addresses two design parameters introduced by the presence of the internal heat transfer plates: the width of the heat transfer plate, which is governed by the amount of heat to be removed and the pressure drop of the cooling water, and the spacing between these heat transfer plates. In order to analyze the performance of the bioreactor a productivity term is introduced that takes into account the volume occupied within the bioreactor by the heat transfer plates. As part of this analysis, it is shown that, for logistic growth kinetics, the time at which the biomass reaches 90 % of its maximum possible value is a good estimate of the optimum harvesting time for maximizing productivity. Application of the productivity analysis to the simulated fermentation results suggests that, with typical fast growing fungi ( = 0.324 h–1), the optimal spacing between heat transfer plates is of the order of 6 cm. The general applicability of this approach to evaluate the productivity of solid-state bioreactors is demonstrated.Opisana je metoda analize rada fermentacijskog bioreaktora sa čvrstim slojem. Postupak je primijenjen da bi se ispitala optimalna vrijednost za razmak između ploča za hlađenje u bioreaktoru Zymotis, koristeći simulirane fermentacijske podatke dobivene prema matematičkom modelu. Bioreaktor Zymotis je vrlo prikladan za one fermentacijske procese u čvrstom sloju u kojima supstratni sloj mora ostati statičan. Opisani postupak koristi dva određena parametra uvjetovana prisutnošću internih ploča za prijenos topline. Širina ploča za prijenos topline uvjetovana je količinom topline koju treba uklonitii padom tlaka rashladne vode te razmakom između tih ploča. Da bi se analizirao učinak bioreaktora, uveden je pojam produktivnosti koji uzima u obzir volumen unutar bioreaktora što ga zauzimaju ploče za prijenos topline. Kao dio ove analize pokazalo se da je, prema logistici kinetike rasta, optimalno vrijeme za povećavanje produktivnosti upravo ono kada biomasa postiže 90 % svoje maksimalne moguće vrijednosti

Biotehnološke mogućnosti tirozinaze gljiva

Over the last decade there has been a significant interest in developing biotechnological applications of tyrosinases. These applications include the production of L-DOPA (3,4-dihydroxyphenyl-L-alanine) from L-tyrosine, the production of cross-linked protein networks for use as novel food additives and the detection of phenolic compounds in wastewater or their removal from it. Much of the research into these applications has involved mushroom tyrosinases. We review the potential biotechnological applications of mushroom tyrosinases and evaluate the state of knowledge about their production, recovery and immobilization. We conclude that much more research is necessary in these areas if mushroom tyrosinases are to fulfill their biotechnological potential.U posljednjem se desetljeću povećalo zanimanje za primjenu tirozinaze u biotehnologiji. Primjena obuhvaća proizvodnju L-DOPA (3,4-dihidroksifenil-L-alanin) iz L-tirozina, proizvodnju umreženih polimera za dodatak hrani te određivanje ili uklanjanje fenolnih spojeva iz otpadnih voda. Veći dio tih istraživanja odnosi se na tirozinazu gljiva. Prikazana je mogućnost primjene tirozinaze gljiva u biotehnologiji i ocijenjene dosadašnje spoznaje o njihovoj proizvodnji, izdvajanju i imobiliziranju. Zaključeno je da je potrebno provesti dodatna istraživanja kako bi se povećala mogućnost primjene tirozinaze gljiva u biotehnologiji

Inhibicija supstrata za proizvodnju tirozinaze s pomoću gljive Lentinula boryana (Berk. & Mont.) Pegler prekurzorom dopamina (L-DOPA)

We undertook a preliminary characterization of the tyrosinase produced by a strain of Lentinula boryana from Brazil, with a view to evaluate its potential for biotechnological applications. The enzyme was similar to other fungal tyrosinases in many respects. When the crude extract was characterized, the tyrosinase activity was optimal at pH=6 and was not particularly thermostable, with half-lives of about 10 min and 1 min at 50 and 60 °C, respectively. We purified the enzyme with ammonium sulfate precipitation followed by ion exchange chromatography on a DEAE Sepharose column, obtaining a yield of 33 % and a 5.3-fold enrichment. The purified preparation gave three bands on SDS-PAGE, with molecular masses of 20, 27 and 47 kDa. This preparation showed substrate inhibition kinetics with L-DOPA (3,4-dihydroxy-L-phenylalanine), with a KM of 1.9 mM and a KI of 72 mM. Under the same reaction conditions, a commercial mushroom tyrosinase followed Michaelis-Menten kinetics, with a KM of 0.51 mM. Although the present study did not identify properties that would make the tyrosinase of L. boryana more suitable in biotechnological applications than tyrosinases from other mushrooms, it has made a contribution by showing that the enzyme suffers substrate inhibition by L-DOPA, something that has not previously been reported for mushroom tyrosinases.Provedena je preliminarna karakterizacija tirozinaze proizvedene brazilskim sojem gljive Lentinula boryana, radi procjene moguće primjene u biotehnologiji. Enzim je po mnogo čemu sličan tirozinazama drugih gljiva. Nakon karakterizacije sirovog ekstrakta, aktivnost tirozinaze bila je optimalna pri pH=6 i ne osobito termostabilna, s poluvremenom raspada od 10 i 1 min pri 50 i 60 °C. Enzim je pročišćen taloženjem pomoću amonijeva sulfata i ionskom kromatografijom na koloni DEAE-sefaroze, s prinosom od 33 % i faktorom obogaćivanja od 5,3. Primjenom metode SDS-PAGE dobivene su 3 trake pročišćenoga proizvoda, molekularne mase od 20, 27 i 47 kDa. Pokazatelji kinetike inhibicije supstrata tog proizvoda s L-DOPA (3,4-dihidroksi-L-fenilalaninom) iznosili su KM=1.9 mM i KI=72 mM. U istim uvjetima reakcije tirozinaza iz komercijalnih gljiva ponašala se prema Michaelis-Mentenovom modelu s vrijednošću KM=0,51 mM. Iako ovim istraživanjem nije ustanovljeno da je tirozinaza iz gljive L. boryana najprikladnija za biotehnološku primjenu, ipak je pridonijelo spoznajom da L-DOPA utječe na inhibiciju supstrata enzima, što dosad nije bilo poznato

Continuous Enzymatic Prehydrolysis Treatment of High-Fat Wastewater

Za obradu otpadnih voda bogatih mastima iz tvornice za preradu mesa i izradu kobasica u São José dos Pinhais, Paraná, Brazil korištena je lipolitička smjesa, proizvedena fermentacijom na čvrstoj podlozi od otpadaka šećerne trske i suncokretove pogače pomoću mikroorganizma Rhizopus microsporus CPQBA 312-07 DRM u bioreaktoru s nasutim slojem nosača. Ovim se načinom obrade pri hidrauličkom vremenu zadržavanja od 24 h smanjio udjel masti i ulja u otpadnim vodama čak i do 96 %, a povećao omjer petodnevne biokemijske potrošnje kisika i kemijske potrošnje kisika (BOD5/COD). Taj je omjer u uzorku netretiranih otpadnih voda bio samo 0,19, što je upućivalo na slabu biorazgradivost, no nakon obrade omjer je porastao na 0,55, što znači da se otpadne vode mogu pročistiti nakon tretmana pomoću aerobnih mikroorganizama ili aktivnog mulja. Mikrobiološkom je analizom potvrđeno da je R. microsporus bio aktivan u fermentiranoj smjesi čak i nakon 96 dana obrade u bioreaktoru. Rezultati pokazuju da se otpadne vode bogate mastima mogu uspješno pročistiti u protočnom bioreaktoru s nasutim slojem nosača koristeći smjesu fermentiranu s pomoću R. microsporus.A lipolytic fermented solid was produced by solid-state fermentation of Rhizopus microsporus CPQBA 312-07 DRM on a mixture of sugarcane bagasse and sunflower seed meal and used, in a packed-bed bioreactor, to pretreat a high-fat wastewater from a meat and sausage processing factory located in São José dos Pinhais, State of Paraná, Brazil. With a hydraulic residence time of 24 h, this pretreatment not only reduced the wastewater’s oil and grease content by up to 96 %, but also increased its 5-day biochemical oxygen demand to chemical oxygen demand (BOD5/COD) ratio. This ratio was only 0.19 in the raw wastewater, indicating poor biodegradability, but increased to 0.55 in the pretreated wastewater, indicating that it had a sufficiently high biodegradability to be sent to a traditional anaerobic digestion or activated sludge process. After 96 days of operation of the packed bed, a microbiological analysis showed that R. microsporus was still present and viable in the fermented solid. Our work shows that a continuous packed-bed bioreactor containing fermented solid produced by R. microsporus has good potential for the treatment of high-fat wastewater