Adenise Lorenci Woiciechowski

Experimental design to enhance the production of l-(+)-lactic acid from steam-exploded wood hydrolysate using Rhizopus oryzae in a mixed-acid fermentation

Abstract The fermentation of hemicellulosic hydrolysate from Pinus taeda chips, using the fungal culture Rhizopus oryzae , was carried out to produce l -(+)-lactic acid and to optimize and enhance the biological conversion of reducing sugar into l -(+)-lactic acid using the experimental design to evaluate the culture conditions. The first factorial design based on surface response with five factors (agitation level, substrate concentration, CaCO 3 concentration, C/N and C/P ratios) at low levels and one medium point was performed to optimize culture conditions. The second study tested two factors (substrate concentration and C/N ratio) at three levels. The statistical analysis of the data obtained from the factorial study showed that a C/N ratio of 35 and substrate concentration of 90 g/litre were the best conditions to produce l -(+)-lactic acid with R. oryzae on P. taeda hydrolysate, but in this case the statistical projection was not correct and the real optimized conditions were C/N ratio of 55 and substrate concentration of 75 g/litre of reducing sugar.

Lignocellulosic Bioethanol: Current Status and Future Perspectives

Publisher Summary Lignocellulosic biomass is an attractive alternative material for bioethanol fuel production. Lignocellulose is the most abundant renewable resource on Earth, and it constitutes a large component of the wastes originating from municipal, agricultural, forestry, and some industrial sources. The more widespread geographical distribution of lignocellulose sources, compared to fossil reserves, can provide security of supply by using domestic sources of energy. The use of lignocellulosic materials would minimize the conflict between land use for food (and feed) production and energy feedstock production. This raw material is less expensive than conventional agricultural feedstock and can be produced with lower input of fertilizers, pesticides, and energy. Biofuels from lignocellulose generate low net GHG (greenhouse gas) emissions, reducing environmental impact, particularly on climate change. Currently, some countries are producing ethanol from cellulosic feedstock at different development stages, and several public/private international projects have been developed in the biorenewable sector to promote a bio-based economy. Depending on the feedstock considered, its availability for bioethanol production can vary considerably from season to season, and depending on geographic locations, could also pose difficulty in their supply. The changes in the price of feedstocks can highly affect the production costs of bioethanol. Because feedstocks typically account for greater than one third of the production costs, maximizing bioethanol yield would be imperative. Each country must find the best and economical way to use their feedstocks and residues in order to produce biofuels. Brazilian bioethanol program is an example of the efficiency of sugarcane production and high technology bioethanol production.

Pretreatment strategies for delignification of sugarcane bagasse: a review

The valorization of agro-residues by biological routes is a key technology that contributes to the development of sustainable processes and the generation of value-added products. Sugarcane bagasse is an agro-residue generated by the sugar and alcohol industry in Brazil (186 million tons per year), composed essentially of cellulose (32-44%), hemicellulose (27-32%) and lignin (19-24%). The conversion of sugarcane bagasse into fermentable sugars requires essentially two steps: pretreatment and hydrolysis. The aim of the pretreatment is to separate the lignin and break the structure of lignocellulose, and it is one of the most critical steps in the process of converting biomass to fermentable sugars. The aim of this review is to describe different pretreatment strategies to promote the delignification of the sugarcane bagasse by thermo-chemical and biological processes.

Citric acid production by solid-state fermentation on a semi-pilot scale using different percentages of treated cassava bagasse

Citric acid is commercailly important product used in several industrial processes. Solid-state fermentation (SSF) has become an alternative method for citric acid production using agro-industrial residues such as cassava bagasse (CB). Use of CB as substrate can avoid the environmental problems caused by its disposal in the environment. The aim of this work was to verify the effect of different percentages of gelatinized starch in CB on production of citric acid by SSF in horizontal drum and tray-type bioreactors. Gelatinization was used in order to make the starch structure more susceptible to consumption by the fungus. The best results (26.9 g/100g of dry CB) were obtained in horizontal drum bioreactor using 100% gelatinized CB, although the tray-type bioreactor offers advantages and shows promise for large-scale citric acid production in terms of processing costs.

Lignin preparation from oil palm empty fruit bunches by sequential acid/alkaline treatment - A biorefinery approach.

Lignin is an important raw material for the sustainable biorefineries and also the forerunner of high-value added products, such as biocomposite for chemical, pharmaceutical and cement industries. Oil palm empty fruit bunches (OPEFB) were used for lignin preparation by successive treatment with 1% (w/w) H2SO4 at 121°C for 60 min and 2.5% NaOH at 121°C for 80 min resulting in the high lignin yield of 28.89%, corresponding to 68.82% of the original lignin. The lignin obtained was characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The results indicated a lignin with molecular masses ramping from 4500 kDa to 12,580 kDa. FTIR and NMR of these lignins showed more syringyl and p-hydroxyphenyl than guaiacyl units. Moderate acid/alkaline treatment provided lignin with high industrial potential and acid hydrolyzates rich in fermentable sugars and highly porous cellulosic fibers.

Steam Explosion Pretreatment of Oil Palm Empty Fruit Bunches (EFB) using autocatalytic hydrolysis: A Biorefinery approach

The oil palm empty fruit bunches (EFB) are an attractive source of carbon for the production of biochemical products, therefore, the aim of this work is to analyze the effect of the steam explosion (SE) pretreatment under autocatalytic conditions on EFB using a full experimental design. Temperature and reaction time were the operational variables studied. The EFB treated at 195°C for 6 min showed an increase of 34.69% in glycan (mostly cellulose), and a reduction of 68.12% in hemicelluloses, with increased enzymatic digestibility to 33% producing 4.2 g L(-1) of glucose. Scanning electron micrographs of the steam treated EFB exhibited surface erosion and an increased fiber porosity. Fourier transform infrared spectroscopy showed the solubilization of hemicellulose and modification of cellulose in treated EFB.

Xanthan gum production from cassava bagasse hydrolysate with Xanthomonas campestris using alternative sources of nitrogen

Cassava bagasse was hydrolyzed using HCl and the hydrolysate was used for the production of xanthan gum using a bacterial culture of Xanthomonas campestris. Cassava bagasse hydrolysate with an initial concentration of approx 20 g of glucose/L proved to be the best substrate concentration for xanthan gum production. Among the organic and inorganic nitrogen sources tested to supplement the medium—urea, yeast extract, peptone, potassium nitrate, and ammonium sulfate—potassium nitrate was most suitable. Ammonium sulfate was the least effective for xanthan gum production, and it affected sugar utilization by the bacterial culture. In media with an initial sugar concentration of 48.6 and 40.4 g/L, at the end of fermentation about 30 g/L of sugars was unused. Maximum xanthan gum (about 14 g/L) was produced when fermentation was carried out with a medium containing 19.8 g/L of initial reducing sugars supplemented with potassium nitrate and fermented for 72 h, and it remained almost the same until the end of fermentation (i.e., 96 h).

Production and Characterization of Amylases by Aspergillus niger under Solid State Fermentation Using Agro Industrials Products

The use of agro industrials products cassava starch and sugar cane bagasse present a great potential as substrate and support, respectively, showing low production costs for amylases production under solid-state fermentation by Aspergillus niger LPB 28. The effect of various factors was examined and some variables were optimized to ?-amylase and amyloglucosidase production. Inoculum rate in different concentrations (105, 106, 107 and 108 spores/g of cassava starch) were used to inoculate the solid substrate for the SSF. The material was supplemented with nitrogen sources; calcium source and micronutrients solution. The ratios of cassava starch to sugar cane bagasse (1/1; 1.5/1; 1/1.5; 1/2; 2/1; 1/3; 3/1) were tested and the initial moisture content varying 80, 85 and 90%. Cultivation was carried out at temperatures 25, 30 and 35ºC for 48, 60 and 72 h. Study of influence of pH initial in SSF was conduced in pH 4.0, 5.0, 6.0, 7.0 and 8.0. Statistical analysis was carried out using the software STATISTICA 5.1 (StatSoft, Tulsa, OK, USA). A 32 complete factorial design (2 factors, 3 levels and 9 experiments) was used to study the effect of the factors in ?-amylase and amyloglucosidase production. The results showed cassava starch and sugar cane bagasse at the ratios of 2/1 was the best for optimum production of ?-amylase and amyloglucosidase. The maximum yield (?-amylase 1732.95 U/g of cassava starch and amyloglucosidase 2044.94 U/g of cassava starch) was achieved with optimized process parameters such as incubation period (60 hours), moisture level was 90%, inoculation rate (105 spores/g of dried material), pH 4.0 and fermentation temperature (30ºC). The nitrogen source (KNO3) also enhanced the ?-amylase and amyloglucosidase activities. In kinetic characterization of enzymes the Michaelis-Menten constant KM and maximum velocity Vmax (KM 10.84 g/l, Vmax 3.42 g/l) for ?-amylase and KM 11.32 g/l and Vmax 5.18 g/l for amyloglucosidase.

Thermoanalytical and starch content evaluation of cassava bagasse as agro-industrial residue

As fracoes nutricionais bem como as propriedades termicas e outras analises sao essenciais para a industria de alimentos e suas aplicacoes O bagaco de mandioca e um importante residuo agroindustrial e seu teor de amido foi avaliado por dois metodos alternativos. A caracterizacao por analise termica e microscopia ajudou na compreensao de como a hidrolise digere a fracao amilacea do bagaco de mandioca, O ponto de fusao foi de 170oC, a analise termogravimetrica (TG) mostrou apos a perda de umidade do material, duas principais perdas de massa em todas as amostras analisadas. Os resultados sugerem que a hidrolise enzimatica e menos eficiente na conversao total de amido no bagaco de mandioca. No entanto, o uso de acido sulfurico degradou ate mesmo a parcela fibrosa do material, afetando as condicoes de analise.

INCREASE IN PHYTASE SYNTHESIS DURING CITRIC PULP FERMENTATION

Citric pulp bran was used for the first time as substrate for phytase synthesis under solid-state fermentation. An A. niger FS3 phytase strain was applied in optimization studies. A Plackett-Burman screening design identified significant physicochemical variables. These preselected variables were subsequently optimized using a central composite rotational design (CCRD). The maximum phytase production was achieved with the following optimum variables: 30°C temperature, 65% initial moisture content, 0.3 M Na-citrate buffer concentration, initial pH 5.0, and 1.5% urea concentration. An overall 4.3-fold improvement in phytase production was successfully achieved.