Influence of nitrogen source and sucrose concentration on inulinase production by Kluyveromyces marxianus in fed-batch fermentation

This work studied the influence of nitrogen source and sucrose concentration in the feeding medium for biomass and inulinase production by Kluyveromyces marxianus var. bulgaricus. The results show that the best nitrogen source was a combination of 5 g/L of yeast extract and 10 g/L of peptone. Both cellular growth and enzymatic activity increased with sucrose concentration in the feeding medium (from 200 to 500 g/L). When the sucrose concentration reached 600 g/L, both cellular growth and enzymatic activity decreased.Key words: Kluyveromyces marxianus, nitrogen, sucrose, inulinase, fed-batch fermentation

Primjena metode odzivnih površina radi optimiranja proizvodnje mliječne kiseline: obogaćivanje podloge, kontrola temperature i pH-vrijednosti

Two response surface methodologies involving central composite designs have been successfully applied to evaluate the effect of cheese whey, corn steep liquor, ammonium sulphate, temperature and pH control on lactic acid fermentation by Lactobacillus sp. LMI8 isolated from cassava flour wastewater. In the first central composite design, corn steep liquor and ammonium sulphate were investigated as low-cost nitrogen sources in combination with other components to substitute yeast extract for economical production. The best results were obtained with 55 g/L of lactose, 15 g/L of corn steep liquor and 5.625 g/L of ammonium sulphate. At the maximum point, the lactic acid concentration reached 18.68 g/L. After defining the optimal nutritional conditions for lactic acid production, a second central composite design was performed to determine the extent to which temperature and pH influence the lactic acid production with the aim of improving the fermentation process. The second-order polynomial regression model determined that the maximum lactic acid production of 52.37 g/L would be obtained when the optimum temperature and pH were 39.6 °C and 5.9, respectively. Comparing the lactic acid production in shake flask fermentation, there was an increase of 180 % after 30 h of processing, with a conversion efficiency of about 86.12 % of the initial lactose. In addition, lactic acid produced from whey lactose by Lactobacillus sp. LMI8 was optically almost pure D-lactic acid (over 98 % of total lactic acid produced).U radu su uspješno primijenjene dvije metode odzivnih površina, uključujući centralno složeni dizajn, za procjenu učinka koncentracije sirutke, ekstrakta kukuruza, amonijeva sulfata, temperature i pH-vrijednosti na mliječno-kiselu fermentaciju uz pomoć bakterije Lactobacillus sp. LMI8, izolirane iz otpadnih voda nakon proizvodnje brašna kasave. U prvom centralno složenom dizajnu ispitani su ekstrakt kukuruza i amonijev sulfat kao jeftini izvori dušika. Utvrđeno je da se u kombinaciji s ostalim sastojcima mogu upotrijebiti kao ekonomični nadomjestak za kvaščev ekstrakt. Najbolji su rezultati postignuti uporabom 55 g/L laktoze, 15 g/L ekstrakta kukuruza i 5,625 g/L amonijeva sulfata, pri čemu je proizvedeno 18,68 g/L mliječne kiseline. Nakon što je određen optimalni sastav hranjiva, proveden je drugi složeno centralno složeni dizajn kako bi se ispitao utjecaj temperature i pH-vrijednosti na proizvodnju mliječne kiseline i poboljšao proces fermentacije. Polinomskim regresijskim modelom drugoga reda određeno je da se maksimalna proizvodnja mliječne kiseline od 52,37 g/L može postići pri temperaturi od 39,6 °C i pH-vrijednosti od 5,9. U usporedbi s fermentacijom na tresilici, koncentracija mliječne kiseline nakon 30 h bila je 180 % veća, a uspješnost konverzije laktoze iznosila 86,12 %. Također je više od 98 % mliječne kiseline proizvedene iz laktoze sirutke s pomoću Lactobacillus sp. LMI8 bila skoro optički čista D-mliječna kiselina

Response surface optimization of D(-)-lactic acid production by Lactobacillus SMI8 using corn steep liquor and yeast autolysate as an alternative nitrogen source

The production of D(-) lactic acid from Lactobacillus LMI8 sp. was studied, using 2 low-cost nitrogen sources: corn steep liquor (CSL) and yeast autolysate (YA). A central composite design was used to determine maximal lactic acid production. The surface response method was used to evaluate theresults of the experiments. The assays were performed in 250 mL Erlenmeyer flasks containing 100 mL of production medium maintained under refrigerated incubation at 200 rpm and a temperature of 37 ± 1°C for 48 h of fermentation. Lactic acid production was significantly affected by the isolated CSL as well as the interaction between CSL and YA. Maximal production of D(+) lactic acid was 41.42 g/L – a value located at the central point, which corresponded to 15 g/L of CSL and 5 g/L of YA

Biodegradability of diesel and biodiesel blends

The biodegradability of pure diesel and biodiesel and blends with different proportions of biodiesel (2%(commercial); 5% and 20%) was evaluated employing the respirometric method and the redox indicator2,6-dichlorophenol indophenol (DCPIP) test. In the former, experiments simulating the contamination of natural environments (soil from a petrol station or water from a river) were carried out in Bartha biometer flasks (250 ml), and used to measure the microbial CO2 production. With the DCPIP test, the capability of three inocula to biodegrade the blends was tested. Results show that although biodiesel is more easily and faster biodegraded than diesel oil, among the blends evaluated (2%, 5% and 20%), only the blend with higher concentration of biodiesel presented biodegradability significantly different from diesel and it was not verified an improvement on the biodegradation of the diesel by means of  cometabolism

Serum metabolomics assessment of etiological processes predisposing ketosis in water buffalo during early lactation

Metabolic disorders as ketosis are manifestations of the animal's inability to manage the increase in energy requirement during early lactation. Generally, buffaloes show a different response to higher metabolic demands than other ruminants with a lower incidence of metabolic problems, although ketosis is one of the major diseases that may decrease the productivity in buffaloes. The aim of this study was to characterize the metabolic profile of Mediterranean buffaloes (MB) associated with 2 different levels of beta-hydroxybutyrate (BHB). Sixty-two MB within 50 days in milk (DIM) were enrolled and divided into 2 groups according to se -rum BHB concentration: healthy group (37 MB; BHB <0.70 mmol/L; body condition score: 5.00; parity: 3.78; and DIM: 30.70) and group at risk of hyperketonemia (25 MB; BHB >= 0.70 mmol/L; body condition score: 4.50; parity: 3.76; and DIM: 33.20). The statistical analysis was conducted by one-way ANOVA and un-paired 2-sample Wilcoxon tests. Fifty-seven metabolites were identified and among them, 12 were significant or tended to be significant. These metabolites were related to different metabolic changes such as mobilization of body resources, ruminal fermentations, urea cycle, thy-roid hormone synthesis, inflammation, and oxidative stress status. These findings are suggestive of metabolic changes related to subclinical ketosis status that should be further investigated to better characterize this dis-ease in the MB

Identification of Lipid Biomarkers to Discriminate between the Different Production Systems for Asiago PDO Cheese

The lipid fraction of Asiago Protected Designation of Origin (PDO) cheese was analyzed to identify specific biomarkers of its main production systems through a canonical discriminant analysis. The three main production systems of the cheese were considered. Two were located in the upland (UL): pasture-based (P-UL) vs hay-based total mixed rations (H-UL). The third was located in the lowland (LL) and processed milk from cows fed maize silage-based rations (maize silage lowland: MS-LL). The discriminant analysis selected nine fatty acids and vitamin A as lipid biomarkers useful to separate the three production systems. High contents of conjugated linoleic acids, anteiso-C15:0, and vitamin A were discriminant factors for P-UL cheese. The separation between H-UL and MS-LL cheese was less marked with the former having the higher content of conjugated linoleic acids and some polyunsaturated n-6 fatty acids and with the latter being identified by cyclopropane fatty acid and C9:0

Descriptive epidemiology of selected birth defects, areas of Lombardy, Italy, 1999

<p>Abstract</p> <p>Background</p> <p>Birth defects are a leading cause of neonatal and infant mortality in Italy, however little is known of the etiology of most defects. Improvements in diagnosis have revealed increasing numbers of clinically insignificant defects, while improvements in treatment have increased the survival of those with more serious and complex defects. For etiological studies, prevention, and management, it is important to have population-based monitoring which provides reliable data on the prevalence at birth of such defects.</p> <p>Methods</p> <p>We recently initiated population-based birth defect monitoring in the Provinces of Mantova, Sondrio and Varese of the Region of Lombardy, northern Italy, and report data for the first year of operation (1999). The registry uses all-electronic source files (hospital discharge files, death certificates, regional health files, and pathology reports) and a proven case-generation methodology, which is described.</p> <p>The data were checked manually by consulting clinical records in hospitals. Completeness was checked against birth certificates by capture-recapture. Data on cases were coded according to the four-digit malformation codes of the International Classification of Diseases, Ninth Revision (ICD-9). We present data only on selected defects.</p> <p>Results</p> <p>We found 246 selected birth defects in 12,008 live births in 1999, 148 among boys and 98 among girls. Congenital heart defects (particularly septal defects) were the most common (90.8/10,000), followed by defects of the genitourinary tract (34.1/10, 000) (particularly hypospadias in boys), digestive system (23.3/10,000) and central nervous system (14.9/10,000), orofacial clefts (10.8/10,000) and Down syndrome (8.3/10,000). Completeness was satisfactory: analysis of birth certificates resulted in the addition of two birth defect cases to the registry.</p> <p>Conclusion</p> <p>This is the first population-based analysis on selected major birth defects in the Region. The high birth prevalences for septal heart defect and hypospadias are probably due to the inclusion of minor defects and lack of coding standardization; the latter problem also seems important for other defects. However the data produced are useful for estimating the demands made on the health system by babies with birth defects.</p

Aerobic biodegradation of butanol and diesel oil blends

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)This work aimed to evaluate the aerobic biodegradation of butanol/diesel oil blends (5, 10, 15, 20%, v/v) in comparison to the biodiesel/diesel oil blend (20%, v/v). Respirometric experiments simulating the contamination of natural environments (soil and water from a river) were carried out in biometer flasks (250 mL) used to measure microbial carbon dioxide (CO(2)) production. The automated turbidimeter Bioscreen C was used to follow the growth of Pseudomonas aeruginosa LBI on butanol/diesel oil blends. A redox indicator (2,6-dichlorophenol indophenol - DCPIP) test was used to evaluate the capability of four inocula to biodegrade the blends with 20% (v/v). The experiment which simulated the soil contamination demonstrated that butanol is less biodegradable than diesel oil, and for this reason the increase in the portion of butanol in the butanol/diesel blend from 5 to 20% had negative effects on biodegradation. While in soil the biodiesel/diesel blend was more easily biodegraded than the butanol/diesel blend, in water this order was the inverse. The insoluble fuels (diesel and biodiesel) were poorly biodegraded in water and the biodegradation of the butanol/diesel blend was favored by the water solubilization of the butanol, which enhances the bioavailability of this compound. On the other hand, initial concentrations of butanol in the water higher than 10 mL L(-1) inhibited the cell growth of the tested microorganisms. Thus, butanol toxicity presumably had a significant effect on the degree of biodegradation of the fuel blends.94270947101Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Agencia Nacional do Petroleo, Gas Natural e Biocombustiveis (ANP) [PRH-05]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2007/00341-1, 2007/07049-4]Agencia Nacional do Petroleo, Gas Natural e Biocombustiveis (ANP) [PRH-05