Expression analysis of transcription factors in sugarcane during cold stress / Análise de expressão de fatores de transcrição em cana-de-açúcar sob estresse por frio

Abstract Transcription factors (TF) are a wide class of genes in plants, and these can regulate the expression of other genes in response to various environmental stresses (biotic and abiotic). In the current study, transcription factor activity in sugarcane was examined during cold stress. Initially, RNA transcript reads of two sugarcane cultivars (ROC22 and GT08-1108) under cold stress were downloaded from SRA NCBI database. The reads were aligned into a reference genome and the differential expression analyses were performed with the R/Bioconductor edgeR package. Based on our analyses in the ROC22 cultivar, 963 TF genes were significantly upregulated under cold stress among a total of 5649 upregulated genes, while 293 TF genes were downregulated among a total of 3,289 downregulated genes. In the GT08-1108 cultivar, 974 TF genes were identified among 5,649 upregulated genes and 283 TF genes were found among 3,289 downregulated genes. Most transcription factors were annotated with GO categories related to protein binding, transcription factor binding, DNA-sequence-specific binding, transcription factor complex, transcription factor activity in RNA polymerase II, the activity of nucleic acid binding transcription factor, transcription corepressor activity, sequence-specific regulatory region, the activity of transcription factor of RNA polymerase II, transcription factor cofactor activity, transcription factor activity from plastid promoter, transcription factor activity from RNA polymerase I promoter, polymerase II and RNA polymerase III. The findings of above results will help to identify differentially expressed transcription factors during cold stress. It also provides a comprehensive analysis of the regulation of the transcription activity of many genes. Therefore, this study provides the molecular basis for improving cold tolerance in sugarcane and other economically important grasses.

Resumo Fatores de transcrição (FT) são uma ampla classe de genes em plantas e podem regular a expressão de outros genes em resposta a vários estresses ambientais (estresses bióticos e abióticos). No presente estudo, a atividade do fator de transcrição na cana-de-açúcar foi examinada durante o estresse pelo frio. Inicialmente, as leituras de transcrição de RNA de duas cultivares de cana-de-açúcar (ROC22 e GT08-1108) sob estresse frio foram baixadas do banco de dados SRA NCBI. As leituras foram alinhadas em um genoma de referência e as análises de expressão diferencial foram realizadas com o pacote R / Bioconductor edgeR. Com base em nossas análises no cultivar ROC22, 963 genes TF foram significativamente regulados positivamente sob estresse pelo frio entre um total de 5.649 genes regulados positivamente, enquanto 293 genes TF foram regulados negativamente entre um total de 3.289 genes regulados negativamente. No cultivar GT08-1108, 974 genes TF foram identificados entre 5.649 genes regulados positivamente e 283 genes TF foram encontrados entre 3.289 genes regulados negativamente. Os fatores de transcrição, em sua maioria, foram anotados com categorias GO relacionadas à ligação de proteína, ligação de fator de transcrição, ligação específica de sequência de DNA, complexo de fator de transcrição, atividade de fator de transcrição em RNA polimerase II, atividade de fator de transcrição de ligação de ácido nucleico, atividade de corepressor de transcrição, sequência específica da região reguladora, atividade do fator de transcrição da RNA polimerase II, atividade do cofator do fator de transcrição, atividade do fator de transcrição do promotor do plastídio, atividade do fator de transcrição do promotor da RNA polimerase I, polimerase II e RNA polimerase III. As descobertas dos resultados acima ajudarão a identificar fatores de transcrição expressos diferencialmente durante o estresse pelo frio. Ele também fornece uma análise abrangente da regulação da atividade de transcrição de muitos genes. Portanto, este estudo fornece base molecular para melhorar a tolerância ao frio em cana-de-açúcar e outras gramíneas economicamente importantes.

Acetone­butanol­ethanol fermentation from sugarcane bagasse hydrolysates: utilization of C5 and C6 sugars

Background: Fuels and chemicals from renewable feedstocks have a growing demand, and acetone, butanol and ethanol (ABE) are some relevant examples. These molecules can be produced by the bacterial fermentation process using hydrolysates generated from lignocellulosic biomass as sugarcane bagasse, one of the most abundant sources of lignocellulosic biomass in Brazil. It originates as a residue in mills and distilleries in the production of sugar and ethanol. Results: In the present work, two strategies to generate hydrolysates of sugarcane bagasse were adopted. The fermentation of the first hydrolysate by Clostridium acetobutylicum DSM 6228 resulted in final concentrations of butanol, acetone and ethanol of 6.4, 4.5 and 0.6 g/L, respectively. On the other hand, the second hydrolysate presented better results (averages of 9.1, 5.5 and 0.8 g/L, respectively), even without the need for nutrient supplementation, since key elements were already present in the medium. The productivity (QP) and yield (YP/S) of the solvents with second hydrolysate were 0.5 g/L•h-1 and 0.4 g/g, respectively. Conclusions: The results described herein open new perspectives for the production of important molecules from residual lignocellulosic biomass for the fuel and chemical industries within the context of second-generation biorefinery.

Carotenoid production in sugarcane juice and synthetic media supplemented with nutrients by Rhodotorula rubra l02

ABSTRACT In order for the use of biological carotenoids to become feasible, it is necessary to have adequate low cost sources and improved methods of cultivation. The aim of this study was to evaluate the effect of supplementation with nitrogen, phosphorus, zinc, and magnesium, on the biomass and carotenoid volumetric production by yeast Rhodotorula rubra L02 using a complex medium (sugarcane juice) and synthetic media (sucrose and maltose) as substrates. The experimental design used for each substrate was randomized in blocks with 16 treatments and 3 repetitions. The treatments were compound for 15 different combinations of nutrients (N; Mg; Zn; P, N + Mg; N + Zn; N + P; Mg + Zn; Mg + P; Zn + P; N + P + Zn; N + P + Mg; N + Zn + Mg; P + Zn + Mg; N + Zn + Mg + P) alone and combined, and a control. The results were submitted to analysis of variance and Tukey test at 5% significance level. Among the treatments evaluated, the highest production of dry biomass, with both maltose and sucrose, was observed for Mg (1.60 g/L and 1.94 g/L, respectively). Additionally, another treatment that stood out in terms of biomass production was the control treatment with maltose (1.54 g/L). After the incubation time, killer activity was not observed since there was no formation of inhibition halo around the L02 yeast.

The potential of the newly isolated thermotolerant yeast Pichia kudriavzevii RZ8-1 for high-temperature ethanol production

Abstract High potential, thermotolerant, ethanol-producing yeasts were successfully isolated in this study. Based on molecular identification and phylogenetic analysis, the isolated thermotolerant yeasts were clustered in the genera of Pichia kudriavzevii, Candida tropicalis, Candida orthopsilosis, Candida glabrata and Kodamea ohmeri. A comparative study of ethanol production using 160 g/L glucose as a substrate revealed several yeast strains that could produce high ethanol concentrations at high temperatures. When sugarcane bagasse (SCB) hydrolysate containing 85 g/L glucose was used as a substrate, the yeast strain designated P. kudriavzevii RZ8-1 exhibited the highest ethanol concentrations of 35.51 g/L and 33.84 g/L at 37 °C and 40 °C, respectively. It also exhibited multi-stress tolerance, such as heat, ethanol and acetic acid tolerance. During ethanol fermentation at high temperature (42 °C), genes encoding heat shock proteins (ssq1 and hsp90), alcohol dehydrogenases (adh1, adh2, adh3 and adh4) and glyceraldehyde-3-phosphate dehydrogenase (tdh2) were up-regulated, suggesting that these genes might play a crucial role in the thermotolerance ability of P. kudriavzevii RZ8-1 under heat stress. These findings suggest that the growth and ethanol fermentation activities of this organism under heat stress were restricted to the expression of genes involved not only in heat shock response but also in the ethanol production pathway.

Statistical tools application on dextranase production from Pochonia chlamydosporia (VC4) and its application on dextran removal from sugarcane juice

ABSTRACT The aim of this study was to optimize the dextranase production by fungus Pochonia chlamydosporia (VC4) and evaluate its activity in dextran reduction in sugarcane juice. The effects, over the P. chlamydosporia dextranase production, of different components from the culture medium were analyzed by Plackett-Burman design and central composite design. The response surface was utilized to determine the levels that, among the variables that influence dextranase production, provide higher production of these enzymes. The enzymatic effect on the removal of dextran present in sugarcane juice was also evaluated. It was observed that only NaNO3 and pH showed significant effect (p<0.05) over dextranase production and was determined that the levels which provided higher enzyme production were, respectively, 5 g/L and 5.5. The dextranases produced by fungus P. chlamydosporia reduced by 75% the dextran content of the sugarcane juice once treated for 12 hours, when compared to the control treatment.

Bioethanol production with different dosages of the commercial Acrylamide polymer compared to a Bioextract in clarifying sugarcane juice

ABSTRACT One of the most important steps is to clarify the juice, which are added synthetic polymer acrylamide base, aiming the fast settling of impurities present in the juice. However, this input is expensive and may have carcinogenic and neurotoxic actions to humans. The search for new natural flocculants that have similarity with the commercial product is of great value. A bioextract that may be promising and has coagulant action is the Moringa oleifera Lam. In this context, the objective of the research was to evaluate the consequences of the use of moringa seed extracts and various concentrations of commercial polymer, such as sedimentation aids in clarifying sugarcane juice in the ethanol production, comparing the efficiency of the bioextract moringa. In the treatment of the juice, excessive addition of flocculants can result in reduction of sugars. The bioflocculant moringa was similar in technological features and the fermentative viability compared to usual dose of commercial polymer in Brazil. The fermentation efficiency was also higher for this flocculant, followed by moringa extract. The results obtained in this research indicate potential to the moringa bioextract, particularly in countries where the doses of flocculants are higher than 5 mg.L-1.

Sugarcane straw as a feedstock for xylitol production by Candida guilliermondii FTI 20037

Abstract Sugarcane straw has become an available lignocellulosic biomass since the progressive introduction of the non-burning harvest in Brazil. Besides keeping this biomass in the field, it can be used as a feedstock in thermochemical or biochemical conversion processes. This makes feasible its incorporation in a biorefinery, whose economic profitability could be supported by integrated production of low-value biofuels and high-value chemicals, e.g., xylitol, which has important industrial and clinical applications. Herein, biotechnological production of xylitol is presented as a possible route for the valorization of sugarcane straw and its incorporation in a biorefinery. Nutritional supplementation of the sugarcane straw hemicellulosic hydrolyzate as a function of initial oxygen availability was studied in batch fermentation of Candida guilliermondii FTI 20037. The nutritional supplementation conditions evaluated were: no supplementation; supplementation with (NH4)2SO4, and full supplementation with (NH4)2SO4, rice bran extract and CaCl2·2H2O. Experiments were performed at pH 5.5, 30 °C, 200 rpm, for 48 h in 125 mL Erlenmeyer flasks containing either 25 or 50 mL of medium in order to vary initial oxygen availability. Without supplementation, complete consumption of glucose and partial consumption of xylose were observed. In this condition the maximum xylitol yield (0.67 g g-1) was obtained under reduced initial oxygen availability. Nutritional supplementation increased xylose consumption and xylitol production by up to 200% and 240%, respectively. The maximum xylitol volumetric productivity (0.34 g L-1 h-1) was reached at full supplementation and increased initial oxygen availability. The results demonstrated a combined effect of nutritional supplementation and initial oxygen availability on xylitol production from sugarcane straw hemicellulosic hydrolyzate.

New cultive medium for bioconversion of C5 fraction from sugarcane bagasse using rice bran extract

The use of hemicellulosic hydrolysates in bioprocesses requires supplementation as to ensure the best fermentative performance of microorganisms. However, in light of conflicting data in the literature, it is necessary to establish an inexpensive and applicable medium for the development of bioprocesses. This paper evaluates the fermentative performance of Scheffersomyces (Pichia) stipitis and Candida guilliermondii growth in sugarcane bagasse hemicellulosic hydrolysate supplemented with different nitrogen sources including rice bran extract, an important by-product of agroindustry and source of vitamins and amino acids. Experiments were carried out with hydrolysate supplemented with rice bran extract and (NH4)2SO4; peptone and yeast extract; (NH4)2SO4, peptone and yeast extract and non-supplemented hydrolysate as a control. S. stipitis produced only ethanol, while C. guilliermondii produced xylitol as the main product and ethanol as by-product. Maximum ethanol production by S. stipitis was observed when sugarcane bagasse hemicellulosic hydrolysate was supplemented with (NH4)2SO4, peptone and yeast extract. Differently, the maximum xylitol formation by C. guilliermondii was obtained by employing hydrolysate supplemented with (NH4)2SO4 and rice bran extract. Together, these findings indicate that: a) for both yeasts (NH4)2SO4 was required as an inorganic nitrogen source to supplement sugarcane bagasse hydrolysate; b) for S. stipitis, sugarcane hemicellulosic hydrolysate must be supplemented with peptone and yeast extract as organic nitrogen source; and: c) for C. guilliermondii, it must be supplemented with rice bran extract. The present study designed a fermentation medium employing hemicellulosic hydrolysate and provides a basis for studies about value-added products as ethanol and xylitol from lignocellulosic materials.

Utilization of molasses and sugar cane bagasse for production of fungal invertase in solid state fermentation using Aspergillus niger GH1

Agro-industrial wastes have been used as substrate-support in solid state fermentation for enzyme production. Molasses and sugarcane bagasse are by-products of sugar industry and can be employed as substrates for invertase production. Invertase is an important enzyme for sweeteners development. In this study, a xerophilic fungus Aspergillus niger GH1 isolated of the Mexican semi-desert, previously reported as an invertase over-producer strain was used. Molasses from Mexico and Cuba were chemically analyzed (total and reducer sugars, nitrogen and phosphorous contents); the last one was selected based on chemical composition. Fermentations were performed using virgin and hydrolyzate bagasse (treatment with concentrated sulfuric acid). Results indicated that, the enzymatic yield (5231 U/L) is higher than those reported by other A. niger strains under solid state fermentation, using hydrolyzate bagasse. The acid hydrolysis promotes availability of fermentable sugars. In addition, maximum invertase activity was detected at 24 h using low substrate concentration, which may reduce production costs. This study presents an alternative method for invertase production using a xerophilic fungus isolated from Mexican semi-desert and inexpensive substrates (molasses and sugarcane bagasse).

Optimization of biodegradable plastic production on sugar cane molasses in Enterobacter sp. SEL2

Contaminated environments have a large number of bacteria which can accumulate PHA as their energy reserves. Out of 54 isolated bacterial strains from three groups of contaminated sites 48 were found PHA positive. The sites were grouped on the basis of the type of carbon sources i.e. sugars, fatty acids and much diverse type. Strains MFD5, MFD11, UML3, USL2, SEL2, SEL3, SEL10 and PFW1 produced 69.9 ± 0.29, 75.27 ± 0.45, 65.43 ± 0.1, 72.54 ± 0.27, 76.61 ± 0.28, 61.81 ± 0.05, 71.16 ± 0.09 and 74.92 ± 0.5 percent of PHA to their constant cell weight (CCW) respectively in PHA detection media supplemented with 2% glucose. Molasses, whey, crumbs hydrolysate and palm oil were checked as inexpensive carbon sources. Molasses alone could supply the required nutrients for growth and PHA production. Strain SEL2 produced 47.36 ± 0.45% PHA using 2% molasses at 37 °C and pH 7.0. Upon production optimization the best accumulation (80.95 ± 0.01%) was observed in PHA detection media with 0.2% nitrogen source, 3% molasses, pH 5.0 and 37 °C by the strain SEL2. The overall effect of the presence of increased molasses concentration in the media was positive it increased the accumulation period till 72 h. Enterobacter sp. SEL2 (JF901810) is first time being reported for PHA production.

Ethanol production from agricultural wastes using Sacchromyces cervisae

The main objective of this study was production of ethanol from three lignocellulosic biomasses like sugarcane bagasse, rice straw and wheat straw by Sacchromyces cervisae. All the three substrates were ground to powder form (2 mm) and pretreated with 3%H2O2 + 2% NaOH followed by steaming at 130 °C for 60 min. These substrates were hydrolyzed by commercial cellulase enzyme. The whole fermentation process was carried out in 500 mL Erlenmeyer flask under anaerobic conditions in submerged fermentation at 30 °C for three days of incubation period. FTIR analysis of the substrates indicated significant changes in the alteration of the structure occurred after pretreatment which leads to efficient saccharification. After pretreatment the substrates were hydrolyzed by commercial cellulase enzyme and maximum hydrolysis was observed in sugarcane bagasse (64%) followed by rice straw (40%) and wheat straw (34%). Among all these tested substrates, sugarcane bagasse (77 g/L) produced more ethanol as compared to rice straw (62 g/L) and wheat straw (44 g/L) using medium composition of (%) 0.25 (NH4)2SO4, 0.1 KH2PO4, 0.05 MgSO4, 0.25 Yeast extract by S. cervisae.

Bioprocessing of some agro-industrial residues for endoglucanase production by the new subsp.; Streptomyces albogriseolus subsp. cellulolyticus strain NEAE-J

The use of low cost agro-industrial residues for the production of industrial enzymes is one of the ways to reduce significantly production costs. Cellulase producing actinomycetes were isolated from soil and decayed agricultural wastes. Among them, a potential culture, strain NEAE-J, was selected and identified on the basis of morphological, cultural, physiological and chemotaxonomic properties, together with 16S rDNA sequence. It is proposed that strain NEAE-J should be included in the species Streptomyces albogriseolus as a representative of a novel sub-species, Streptomyces albogriseolus subsp. cellulolyticus strain NEAE-J and sequencing product was deposited in the GenBank database under accession number JN229412. This organism was tested for its ability to produce endoglucanase and release reducing sugars from agro-industrial residues as substrates. Sugarcane bagasse was the most suitable substrate for endoglucanase production. Effects of process variables, namely incubation time, temperature, initial pH and nitrogen source on production of endoglucanase by submerged fermentation using Streptomyces albogriseolus subsp. cellulolyticus have been studied. Accordingly optimum conditions have been determined. Incubation temperature of 30 ºC after 6 days, pH of 6.5, 1% sugarcane bagasse as carbon source and peptone as nitrogen source were found to be the optimum for endoglucanase production. Optimization of the process parameters resulted in about 2.6 fold increase in the endoglucanase activity. Therefore, Streptomyces albogriseolus subsp. cellulolyticus coud be potential microorganism for the intended application.

Degradabilidade ruminal e parâmetros da fermentação em dietas contendo silagem de cana-de-açúcar e caroço de algodão / Ruminal degradabilityand fermentative parameters in diets with sugarcane silage and whole cottonseed / Degradabilidad ruminal y parámetros de fermentación en dietas que contienen ensilado de caña de azúcar y semilla de algodón

O objetivo do presente trabalho foi avaliar a inclusão de níveis crescentes (5, 10 e 15%) de caroço de algodão à uma dieta de silagem cana-de-açúcar confeccionada com 1% de ureia em base de matéria seca e concentrado composto de milho e farelo de algodão. Foram avaliadas a composição química, as concentrações de ácidos graxos, nitrogênio amoniacal e valores de pH da amostra do líquido ruminal, a cinética ruminal, os parâmetros de degradabilidade in situ da matéria seca e da fibra em detergente neutro da silagem de cana-de-açúcar. Além da eficácia dos indicadores externos LIPE® e dióxido de titânio nas estimativas de produção fecal. Foram utilizadas quatro vacas mestiças Holandês x Zebu fistuladas no rúmen, em um delineamento em Quadrado Latino 4 x 4, no terço inicial da lactação (60 ± 25 dias) e com produção média de 11,1±3,3 kg de leite/dia. Dentre os parâmetros de fermentação e cinética ruminal, somente a concentração ruminal (mMoles/100 mL) e a proporção molar (%) do propionato não sofreram influência (P>0,05) dos tratamentos. Dentre os parâmetros de degradabilidade in situ da matéria seca, tanto a taxa de degradação (c) (0,0458; 0,0372; 0,033 e 0,0147 /h) quanto a degradabilidade efetiva (DE) para uma taxa de passagem de 3,9% (44,26; 46,06; 44,53; e 38,74%) para os tratamentos com 0; 5; 10 e 15% de caroço de algodão, respectivamente, reduziram seus valores com a adição de caroço de algodão a um nível de significância de 5%...

The aim of this study is to evaluate the inclusion of increasing levels (0, 5, 10 and 15%) of cottonseed to a basic sugarcane silage diet made with 1% urea in dry matter basis and concentrate composed of corn and cottonseed meal. The chemical and kinetic parameters were analyzed on in situ dry matter of sugarcane silage, as well as neutral detergent fiber were analyzed. The effectiveness of LIPE® external indicators and titanium dioxide were analyzed in the estimates of fecal production. Four crossbred Holstein dairy cows, fitted with rumen cannulas, in a randomized Latin Squares 4x4 design in the early lactation stage (60 ± 25 days) and average production of 11.1 ±3.3kg milk/day were analyzed. Among the fermentation and kinetic parameters, only ruminal concentration (mMoles/100 ml) and the propionate molar ratio (%)were not influenced (P> 0.05) by the treatments. Among the parameters of in situ dry matter, both the rate of degradation (c) (0.0458, 0.0372, 0.033 and 0.0147 / h) and the effective degradability (DE) for a passage rate of 3.9% (44.26, 46.06, 44.53, and 38.74%) for 0, 5, 10 and 15% cottonseed treatments, respectively, reduced their values with the addition of whole cottonseed at a 5% significance level...

El objetivo de este estudio fue evaluar la inclusión de niveles crecientes (5, 10 y 15%) de semilla de algodón a una dieta de ensilaje de caña de azúcar con 1% de urea en base de materia seca y concentrado compuesto por maíz y harina de semilla de algodón. Se evaluó la composición química, concentraciones de ácidos grasos, nitrógeno amoniacal y valores de pH de muestra del líquido ruminal, la cinética ruminal, los parámetros de degrabilidad in situ de la materia seca y de la fibra en detergente neutra de ensilado de caña de azúcar. Además de la eficacia de los indicadores externos LIPE® y dióxido de titanio en las estimaciones de producción de heces. Se utilizó cuatro vacas mestizas Holstein y Cebú fistuladas en el rumen, en un delineamiento en Cuadrado Latino 4 x 4, en el tercio inicial de la lactación (60 ± 25 días) y con producción promedia de 11,1 ± 3,3 kg de leche/día. Entre los parámetros de fermentación y cinética ruminal, sólo la concentración ruminal (mMoles/100 ml) y la proporción molar (%) de propionato no sufrieron influencia (P> 0,05) de los tratamientos...

Filamentous fungi and media for cellulase production in solid state cultures

Cellulase production was evaluated in two reference strains (T. reesei Rut-C30 and T. reesei QM9414), two strains isolated from a sugarcane cultivation area (Trichoderma sp. IPT778 and T. harzianum rifai IPT821) and one strain isolated in a program for biodiversity preservation in São Paulo state (Myceliophthora thermophila M77). Solid state cultures were performed using sugarcane bagasse (C), wheat bran (W) and/or soybean bran (S). The highest FPA was 10.6 U/gdm for M77 in SC (10:90) at 80% moisture, which was 4.4 times higher than production in pure W. C was a strong inducer of cellulase production, given that the production level of 6.1 U/gdm in WC (40:60) was 2.5 times higher than in pure W for strain M77; T. reesei Rut-C30 did not respond as strongly with about 1.6-fold surplus production. S advantageously replaced W, as the surplus production on SC (20:80) was 2.3 times relative to WC (20:80) for M77.

Effects of agitation and exogenous H2 on bioconversion of sugarcane bagasse into ethanol by Clostridium thermocellum ATCC 27405

Background: The production of ethanol by a Consolidated Bioprocessing (CBP) strategy, which simultaneously combines cellulase production, lignocellulosic biomass hydrolysis and fermentation of released sugars to ethanol in one bioreactor, is a promising technology for cost reduction in the biological processing of biomass, specially using agroindustrial residues. Clostridium thermocellum is an anaerobic, thermophilic, strictly fermentative gram positive bacterium that meets all the requirements for CBP. Results: Ethanol concentration obtained in the non-stirred fermentation process in flasks with raw bagasse was two times greater than that in the stirred system. The results observed using a pretreated sugarcane bagasse in non-stirred flasks regarding ethanol concentration, were slightly lower than with raw bagasse. The sparging of exogenous H2 into the medium at atmospheric pressure inside the bioreactor showed to be unfavourable to achieve higher ethanol yields. Conclusions: The strain investigated is a promising candidate for thermophilic fermentative ethanol production from dried ground raw sugarcane bagasse in a CBP strategy, although the alcohol concentrations need to be further improved. In future studies, it is recommended to investigate different modes of operation of the fermentation process, including pressurized conditions, as well as to use wet raw sugarcane bagasse aiming to achieve additional improvement in ethanol production and to reduce the costs of the process.

Solving ethanol production problems with genetically modified yeast strains

The current world demand for bioethanol is increasing as a consequence of low fossil fuel availability and a growing number of ethanol/gasoline flex-fuel cars. In addition, countries in several parts of the world have agreed to reduce carbon dioxide emissions, and the use of ethanol as a fuel (which produces fewer pollutants than petroleum products) has been considered to be a good alternative to petroleum products. The ethanol that is produced in Brazil from the first-generation process is optimized and can be accomplished at low cost. However, because of the large volume of ethanol that is produced and traded each year, any small improvement in the process could represent a savings of billions dollars. Several Brazilian research programs are investing in sugarcane improvement, but little attention has been given to the improvement of yeast strains that participate in the first-generation process at present. The Brazilian ethanol production process uses sugarcane as a carbon source for the yeast Saccharomyces cerevisiae. Yeast is then grown at a high cellular density and high temperatures in large-capacity open tanks with cells recycle. All of these culture conditions compel the yeast to cope with several types of stress. Among the main stressors are high temperatures and high ethanol concentrations inside the fermentation tanks during alcohol production. Moreover, the competition between the desired yeast strains, which are inoculated at the beginning of the process, with contaminants such as wild type yeasts and bacteria, requires acid treatment to successfully recycle the cells. This review is focused on describing the problems and stressors within the Brazilian ethanol production system. It also highlights some genetic modifications that can help to circumvent these difficulties in yeast.

Sugarcane bagasse as feedstock for cellulase production by Trichoderma harzianum in optimized culture medium

This work aimed at the production of cellulases from pretreated sugarcane bagasse by the filamentous fungus Trichoderma harzianum IOC 3844 and their application in the hydrolysis of this same substrate, for a future use in second-generation ethanol production. The production of cellulases was optimized, which resulted in high enzymatic activities after 42 hrs of process in an instrumented bioreactor (CMCase 27,017 U x L-1; FPase 1,225 U x L-1; and β-glucosidase 609 U x L-1). The enzymatic extract was concentrated by using a hollow fiber membrane filtration system. The concentrated extract was applied in the hydrolysis of pretreated sugarcane bagasse, after 28 hrs of enzymatic reaction, displaying a similar catalytic performance of that attained with a commercial enzymatic preparation (hydrolysis efficiency of roughly 50%). Finally, the enzymatic extract was partially characterized in terms of the molecular weights of the main activities of the enzymatic pool. Electrophoretic analysis identified eleven protein bands; six of them were related to CMCase activity and revealing molecular weights that varied from 48 to 78 kDa, and two bands were associated with β-glucosidase activity and having molecular weights of 75 and 85 kDa.

Flavonóides e ácidos cinâmicos de cana-de-açúcar (Saccharum officinarum L. Poaceae) e seus produtos. Identificação e atividade antioxidante e antiproliferativa / Flavonoids and cinnamic acid from sugarcane (Saccharum officinarum L. Poaceae) and their products: identification of antioxidant and antiproliferative activity

Os produtos obtidos a partir da cana-de-açúcar possuem, além de altas concentrações de sacarose, flavonóides que podem atuar como quimiopreventivos e antioxidantes. Neste estudo foram elucidadas as estruturas dos flavonóides e dos ácidos cinâmicos mais abundantes no caldo de cana, sendo apresentadas duas novas substâncias, uma flavona, tricina-7-Ο-ß-(6"-p-metoxicinamato)-glucosideo e uma lignana, 3-hidroxi-1-[4,5-dihidroxi-3-metoxifenil]-2-[4-(3-hidroxi-1-(E)-propenil)-2,6-dimetoxifenoxi]-propil-ß-D-glucopiranosídeo. Entre as flavonas analisadas, o derivado de tricina apresentou maior abundância. Foi também confirmada neste estudo a perda de compostos fenólicos durante o processamento industrial do açúcar. Nos colmos de cana-de-açúcar evidenciamos altas concentrações de ácidos clorogênico e cumárico, e baixos teores de flavonóides. No decorrer do processamento verificaram-se perdas significativas de ácidos cinâmicos e aumento nos teores de flavonóides. Os maiores teores foram verificados no xarope e os menores no açúcar VHP. Entretanto, a proporção dos compostos fenólicos teve pouca alteração durante o processamento. As flavonas encontradas na cana in natura se mantiveram durante todo o processamento, enquanto que não se detectou ácido ferúlico nas variedades e ácido caféico nos produtos. A atividade antioxidante dos produtos obtidos durante as etapas do processamento do açúcar foram avaliadas. As maiores atividades foram encontradas no xarope e melaço, enquanto que as menores, no caldo misto e açúcar VHP. Uma avaliação sobre o perfil dos compostos fenólicos de amostras de rapadura e caldo de cana obtidos no comércio local mostrou que a rapadura apresenta altos teores de luteolina, enquanto no caldo, prevalece tricina. Nas amostras de rapadura destacam-se altos teores de ácido clorogênico, composto que se mostrou ausente nas amostras obtidas durante as etapas do processamento industrial do açúcar. As atividades antioxidantes dos extratos de rapadura mostraram que mesmo em baixas concentrações a atividade é moderada. O caldo apresentou atividade semelhante, mas em concentrações mais elevadas. Quanto à atividade antiproliferativa, o extrato de rapadura apresentou atividades citostáticas para todas as linhagens e citocida para as linhagens de células cólon (HT-29), de mama (MCF-7), de mama resistente (NCI-ADR), de pulmão (NCI-460), de ovário (OVCAR), de rim (786-0) e de melanoma (UACC-62). O derivado de tricina, isolado a partir do caldo de cana, apresentou atividade antioxidante moderada. Suas atividades antiproliferativas foram mais pronunciadas para as linhagens de células de mama resistente (NCI-ADR) e de cólon (HT-29), com atividade citostática e citocida para as linhagens de pulmão (NCI-460), de mama (MCF-7), de ovário (OVCAR), de rim (786-0) e de melanoma (UACC-62).

Sugar cane products have high sucrose concentration and flavonoids that can function with chemopreventive and antioxidant. In this study have been elucidated flavonoids and cinnamic acids structures most abundant in sugar cane juice and were presented two new substances, one flavone, tricin-7-Ο-ß-(6-methoxycinnamic)-glucoside and one lignan, 3-hydroxy-1-[4,5-dihydroxy-3-methoxyphenyl]-2-[4-(3-hydroxy-1-(E)-propenyl)-2,6-dimethoxyphenoxy]-propyl-ß-D-glucopyranoside. Among the flavones analyzed, tricin presents high concentration. In this study was corroborated the loss of phenolic compounds during the processing industrial of sugar. In culm of sugar have been evidenced high concentrations of the chlorogenic and coumaric acids, and low flavonoid contents. During the processing has been proved significant loss of cinnamic acids and increase of flavonoids. The highest contents have been proved in the syrup and the smallest in the sugar VHP. However, the profile of the phenolic compounds had little alteration during the processing. The flavones finded in sugar cane in natura were remaining during all the processing and, are not find ferulic acid in the varieties and caffeic acid in the products. The antioxidant activities in products obtained during processing stage of sugar cane were evaluated. The highest activities were finded in the syrup and molasses and the smallest in sugar cane juice and sugar VHP. Assessment about the profile of the phenolic compounds in rapadura and sugar cane juice acquired in local commerce showed that the rapadura presents high contents of the luteolina, while in sugar cane juice, predominate tricin. In the sample of rapadura stand out high chlorogenic acid contents, compound that showed absent in sample from during the processing industrial stages of sugar. The antioxidants activities of rapadura extracts showed the in spite of in low concentration the activity is moderate. The sugar cane juice presented similar activity but, in high concentration. As for the antiproliferative activity, the rapadura extract presented cytostatic effect for ali lines and cytocidal for the colon cell lines (HT-29), of breast (MCF-7), of multi-drug resistant breast cells (NCI-ADR), of lung (NCI-460), of ovary (OVCAR), of kidney (786-0), and of melanoma (UACC-62). Tricin, isolated from sugar cane juice, presented moderate antioxidant activity. The antiproliferative effects of tricin were more pronunciated for multi-drug resistant breast cells (NCIADR) and of colon (HT-29), with cytostatic effect and cytocidal for lung lines (NCI460), of breast (MCF-7), ovary (OVCAR), of kidney (786-0), and of melanoma (UACC-62).