Navegando por Palavras-chave "Volumetric oxygen mass transfer coefficient"

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    Impact of oxygen supply on surfactin biosynthesis using brewery waste as substrate
    (Elsevier, 2021-03-15) Zanutto, Talita Corrêa Nazareth; Zanutto, Conrado Planas; Maass, Danielle [UNIFESP]; Souza, Antônio Augusto Ulson de; Souza, Selene Maria de Arruda Guelli Ulson de; http://lattes.cnpq.br/3431482044015696
    This work reports surfactin production by B. subtilis ATCC 6051 in a stirred tank bioreactor, where trub was used as a carbon source. Trub is a residue from the brewing industry mainly composed of high-molar-mass proteins and reducing sugars, being a sustainable and low-cost substrate for bioprocess. Despite this, Trub has been little explored as a raw material in bioprocesses. Aiming to evaluate important factors in scale-up process, the impact of oxygen transfer coefficient (KLa) concerning volumetric productivity, and the effect of agitation (150–300 rpm) and aeration (0.5–1.5 vvm) on biosurfactant production by a Full Factorial design were evaluated. Only agitation presented a significant effect on surfactin concentration (SF), where SF was described by a linear regression model (R2 = 0.99). The biosurfactant showed high stability in relation to variations in temperature and pH. In addition, the foam collecting was an efficient method in recovering and enrichment of the product.
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    Scale up of xylitol production from sugarcane bagasse hemicellulosic hydrolysate by Candida guilliermondii FTI 20037
    (Elsevier Science Inc, 2017) de Arruda, Priscila Vaz [UNIFESP]; dos Santos, Julio Cesar; Lacerda Brambilla Rodrigues, Rita de Cassia; Virginio da Silva, Debora Danielle; Yamakawa, Celina Kiyomi; de Moraes Rocha, George Jackson; Nolasco Junior, Jonas; da Cruz Pradella, Jose Geraldo; Vaz Rossell, Carlos Eduardo; Felipe, Maria das Gracas de Almeida
    In this study, volumetric oxygen mass transfer coefficient (kappa(L)a) was selected as a criterion for facilitating the scale up of xylitol production by Candida guilliermondii at the bench and pilot-scale level. A kappa(L)a value of 16 (h-1) was applied in reactors with volumetric capacity of 2.4 L, 18 L and 125 L Fermentation was successfully scaled-up from the bench to pilot-scale level with all experiments demonstrating a minimum of 60% xylose to xylitol conversion efficiency. Under all evaluated conditions glycerol and ethanol were also produced as by-products of xylose metabolism. Only minor differences were observed in the fermentation profile when reactor volumes ranging from 2.4 L to 125 L were used for experimentation purposes, reaching, at pilot scale, yield and volumetric productivity of 0.55 g g(-1) and 0.31 g L-1 h-1, respectively, with maximum specific growth rate of 0.26 h(-1). This demonstrates and reinforces the feasibility of using kLa as scale up criterion. The use of this parameter allowed precise reproduction of results obtained at bench bioreactor level to a larger scale