2,368 research outputs found
Second generation bioethanol production: on the use of pulp and paper industry wastes as feedstock
Due to the health and environment impacts of fossil fuels utilization, biofuels have been
investigated as a potential alternative renewable source of energy. Bioethanol is currently the most
produced biofuel, mainly of first generation, resulting in food-fuel competition. Second generation
bioethanol is produced from lignocellulosic biomass, but a costly and difficult pretreatment is required.
The pulp and paper industry has the biggest income of biomass for non-food-chain production, and,
simultaneously generates a high amount of residues. According to the circular economy model,
these residues, rich in monosaccharides, or even in polysaccharides besides lignin, can be utilized
as a proper feedstock for second generation bioethanol production. Biorefineries can be integrated
in the existing pulp and paper industrial plants by exploiting the high level of technology and
also the infrastructures and logistics that are required to fractionate and handle woody biomass.
This would contribute to the diversification of products and the increase of profitability of pulp and
paper industry with additional environmental benefits. This work reviews the literature supporting
the feasibility of producing ethanol from Kraft pulp, spent sulfite liquor, and pulp and paper sludge,
presenting and discussing the practical attempt of biorefineries implementation in pulp and paper
mills for bioethanol production.publishe
Two-stage aeration fermentation strategy to improve bioethanol production by scheffersomyces stipitis
Hardwood spent sulfite liquor (HSSL) is a by-product from pulp industry with a high
concentration of pentose sugars, besides some hexoses suitable for bioethanol production by
Scheffersomyces stipitis. The establishment of optimal aeration process conditions that results in
specific microaerophilic conditions required by S. stipitis is the main challenge for ethanol production.
The present study aimed to improve the ethanol production from HSSL by S. stipitis through a
two-stage aeration fermentation. Experiments with controlled dissolved oxygen tension (DOT) in the
first stage and oxygen restriction in the second stage were carried out. The best results were obtained
with DOT control at 50% in the first stage, where the increase of oxygen availability provided faster
growth and higher biomass yield, and no oxygen supply with an agitation rate of 250 rpm, in the
second stage allowed a successful induction of ethanol production. Fermentation using 60% of HSSL
(v/v) as substrate for S. stipitis provided a maximum specific growth rate of 0.07 h−1
, an ethanol
productivity of 0.04 g L h−1 and an ethanol yield of 0.39 g g−1
, respectively. This work showed a
successful two-stage aeration strategy as a promising aeration alternative for bioethanol production
from HSSL by S. stipitis.publishe
Enzymatic Potential of Filamentous Fungi as a Biological Pretreatment for Acidogenic Fermentation of Coffee Waste
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials (UIDB/50011/2020, UIDP/50011/2020, and LA/P/0006/2020), and the Associate Laboratory for Green Chemistry-LAQV (UIDB/50006/2020 and UIDP/50006/2020). It was financed by national funds through the FCT/MCTES (PIDDAC) and, when appropriate, co-financed by FEDER under the PT2020 Partnership Agreement. Paulo C. Lemos acknowledges the support of FCT/MCTES for contract IF/01054/2014/CP1224/CT0005 and Joana Pereira thanks FCT/MCTES for her Ph.D. grant SFRH/BD/130003/2017.Spent coffee grounds (SCGs) are a promising substrate that can be valorized by biotechnological processes, such as for short-chain organic acid (SCOA) production, but their complex structure implies the application of a pretreatment step to increase their biodegradability. Physicochemical pretreatments are widely studied but have multiple drawbacks. An alternative is the application of biological pretreatments that include using fungi Trametes versicolor and Paecilomyces variotii that naturally can degrade complex substrates such as SCGs. This study intended to compare acidic and basic hydrolysis and supercritical CO 2 extraction with the application of these fungi. The highest concentration of SCOAs, 2.52 gCOD/L, was achieved after the acidification of SCGs pretreated with acid hydrolysis, but a very similar result, 2.44 gCOD/L, was obtained after submerged fermentation of SCGs by T. versicolor. This pretreatment also resulted in the best acidification degree, 48%, a very promising result compared to the 13% obtained with the control, untreated SCGs, highlighting the potential of biological pretreatments.publishersversionpublishe
Ethanol production from hydrolyzed kraft pulp by mono- and co-cultures of yeasts: the challenge of C6 and C5 sugars consumption
Second-generation bioethanol production’s main bottleneck is the need for a costly and
technically di cult pretreatment due to the recalcitrance of lignocellulosic biomass (LCB). Chemical
pulping can be considered as a LCB pretreatment since it removes lignin and targets hemicelluloses
to some extent. Chemical pulps could be used to produce ethanol. The present study aimed to
investigate the batch ethanol production from unbleached Kraft pulp of Eucalyptus globulus by
separate hydrolysis and fermentation (SHF). Enzymatic hydrolysis of the pulp resulted in a glucose
yield of 96.1 3.6% and a xylose yield of 94.0 7.1%. In an Erlenmeyer flask, fermentation of the
hydrolysate using Saccharomyces cerevisiae showed better results than Sche ersomyces stipitis. At both
the Erlenmeyer flask and bioreactor scale, co-cultures of S. cerevisiae and S. stipitis did not show
significant improvements in the fermentation performance. The best result was provided by S.
cerevisiae alone in a bioreactor, which fermented the Kraft pulp hydrolysate with an ethanol yield
of 0.433 g g1 and a volumetric ethanol productivity of 0.733 g L1 h1, and a maximum ethanol
concentration of 19.24 g L1 was attained. Bioethanol production using the SHF of unbleached Kraft
pulp of E. globulus provides a high yield and productivity.publishe
Insights into the posttranslational structural heterogeneity of thyroglobulin and its role in the development, diagnosis, and management of benign and malignant thyroid diseases
Thyroglobulin (Tg) is the major glycoprotein produced by the thyroid gland, where it serves as a template for thyroid hormone synthesis and as an intraglandular store of iodine. Measurement of Tg levels in serum is of great practical importance in the follow-up of differentiated thyroid carcinoma (DTC), a setting in which elevated levels after total thyroidectomy are indicative of residual or recurrent disease. The most recent methods for serum Tg measurement are monoclonal antibody-based and are highly sensitive. However, major challenges remain regarding the interpretation of the results obtained with these immunometric methods, particularly in patients with endogenous antithyroglobulin antibodies or in the presence of heterophile antibodies, which may produce falsely low or high Tg values, respectively. The increased prevalence of antithyroglobulin antibodies in patients with DTC, as compared with the general population, raises the very pertinent possibility that tumor Tg may be more immunogenic. This inference makes sense, as the tumor microenvironment (tumor cells plus normal host cells) is characterized by several changes that could induce posttranslational modification of many proteins, including Tg. Attempts to understand the structure of Tg have been made for several decades, but findings have generally been incomplete due to technical hindrances to analysis of such a large protein (660 kDa). This review article will explore the complex structure of Tg and the potential role of its marked heterogeneity in our understanding of normal thyroid biology and neoplastic processes.FapespCNPqCapesUniv Fed Sao Paulo EPM Unifesp, Escola Paulista Med, Lab Endocrinol Mol & Translac, Div Endocrinol & Metab,Dept Med, Sao Paulo, SP, BrazilUniv Fed Mato Grosso do Sul UFMS, Fac Med Famed, Dept Med, Clin Integrada 5,Endocrinol & Metab, Campo Grande, MS, BrazilUniv Fed Sao Paulo, EPM, Dept Bioquim, Div Mol Biol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo EPM Unifesp, Escola Paulista Med, Lab Endocrinol Mol & Translac, Div Endocrinol & Metab,Dept Med, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, EPM, Dept Bioquim, Div Mol Biol, Sao Paulo, SP, BrazilWeb of Scienc
Getting Value from Pulp and Paper Industry Wastes: On the Way to Sustainability and Circular Economy
The pulp and paper industry is recognized as a well-established sector, which throughout its process, generates a vast amount of waste streams with the capacity to be valorized. Typically, these residues are burned for energy purposes, but their use as substrates for biological processes could be a more efficient and sustainable alternative. With this aim, it is essential to identify and characterize each type of waste to determine its biotechnological potential. In this context, this research highlights possible alternatives with lower environmental impact and higher revenues. The bio-based pathway should be a promising alternative for the valorization of pulp and paper industry wastes, in particular for bioproduct production such as bioethanol, polyhydroxyalkanoates (PHA), and biogas. This article focuses on state of the art regarding the identification and characterization of these wastes, their main applied deconstruction technologies and the valorization pathways reported for the production of the abovementioned bioproductspublishe
Valorization of brewer’s spent grain by furfural recovery/removal from subcritical water hydrolysates by pervaporation
This work is focused on the development of a sustainable process for the valorisation of the main by-product
generated in the brewing industry, the brewer’s spent grain (BSG). A two-step process combining subcritical
water treatment and pervaporation (PV) was proposed to hydrolyse the hemicelluloses fraction of this lignocellulosic biomass and further removal/recovery of some of the degradation products of sugars by using two
different organophilic membranes, polydimethylsiloxane (PDMS) and polyoctilmethylsiloxane (POMS) membranes. Specifically, furfural is the dehydration product of pentoses and it is one of the top biomass-based
chemicals being an important platform chemical. For synthetic binary mixtures, lower total permeation flux
but higher enrichment factors for furfural were determined for POMS. When dealing with subW hydrolysates,
POMS membranes yielded the highest furfural recovery, 94.1 %, with permeate concentrations as high as 40 g⋅L1
. Furthermore, it was assessed that PV is a suitable detoxification method that yielded a retentate nearly free of
furfural allowing its use as growth media in the opposite to the subW hydrolysate with inhibitory furfural
concentrations for microbial bioprocesses.publishe
Image analysis technique as a tool to identify morphological changes in Trametes versicolor pellets according to exopolysaccharide or laccase production
Image analysis technique was applied to identify morphological changes of pellets from white-rot fungus Trametes versicolor on agitated submerged cultures during the production of exopolysaccharide (EPS) or ligninolytic enzymes. Batch tests with four different experimental conditions were carried out. Two different culture media were used, namely yeast medium or Trametes defined medium and the addition of lignolytic inducers as xylidine or pulp and paper industrial effluent were evaluated. Laccase activity, EPS production, and final biomass contents were determined for batch assays and the pellets morphology was assessed by image analysis techniques. The obtained data allowed establishing the choice of the metabolic pathways according to the experimental conditions, either for laccase enzymatic production in the Trametes defined medium, or for EPS production in the rich Yeast Medium experiments. Furthermore, the image processing and analysis methodology allowed for a better comprehension of the physiological phenomena with respect to the corresponding pellets morphological stages.The authors acknowledge Portucel-Empresa de Celulose e Papel, Cacia, Portugal, SA for the pulp and paper Kraft effluent used in this work. This work was funded by FEDER Funds through the Programa Operacional Factores de Competitividade-COMPETE, and national funds through FCT-Fundacao para a Ciencia e a Tecnologia under the projects PEst-C/CTM/LA/0011/2013 and PEst-C/EQB/LA0020/2013. A. P. M. Tavares acknowledge the financial support of (Programme Ciencia 2008) FCT, Portugal
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