RESUMO
Biodiesel is an interesting alternative to petroleum diesel as it is renewable, biodegradable, and has a low pollutant content. Yeast oils can be used for biodiesel production instead of edible oils, mitigating the use of arable land and water for biodiesel production. Maximum lipid accumulation is reached at 48 h of cultivation by the oleaginous yeast Papiliotrema laurentii UFV-1. Nevertheless, the effects of carbon and nitrogen concentrations on lipid accumulation, as well as the regulation of lipid metabolism in this yeast are still not well-characterised. Therefore, this work evaluated the effects of carbon and nitrogen concentrations on the lipid accumulation in P. laurentti, the expression of the ACC gene, and the activity of the enzyme acetyl-CoA carboxylase (ACCase) in different carbon:nitrogen ratios (C:N) and glucose concentrations. The variation of ammonium sulfate concentration did not affect the growth and lipid accumulation in P. laurentii UFV-1. On the other hand, glucose concentration remarkably influenced biomass and lipid production by this yeast. Therefore, the carbon concentration is more important than the nitrogen concentration for lipid production by P. laurentii UFV-1. Importantly, the levels of both ACC gene expression and ACCase activity were maximum during the late-exponential growth phase and decreased after reaching the highest lipid contents, which was easier evidenced during the accumulation and maximum lipid levels. As such, the reduction of ACCase enzyme activity seems to be related to the decrease in the expression level of the ACC gene.
RESUMO
In this work, we isolated and selected oleaginous yeasts from rock field soils from two National Parks in Brazil (Caparaó and Serra dos Órgãos) with the potential to accumulate oil from xylose, the main pentose sugar found in lignocellulosic biomass. From the 126 isolates, two were selected based on their lipid contents. They were taxonomically identified as Papiliotrema laurentii (UFV-1 and UFV-2). Of the two, P. laurentii UFV-1 was selected as the best lipid producer. Under unoptimized conditions, lipid production by P. laurentii UFV-1 was higher in glucose than in xylose. To improve its lipid production from xylose, we applied response surface methodology (RSM) with a face-centered central composite design (CCF). We evaluated the effects of agitation rate, initial cell biomass (OD600), carbon/nitrogen ratio (C/N ratio) and pH on lipid production. P. laurentii UFV-1 recorded the highest lipid content, 63.5% (w/w) of the cell dry mass, under the following conditions: C/N ratio = 100:1, pH value = 7.0, initial OD600 = 0.8 and agitation = 300 rpm. Under these optimized conditions, biomass, lipid titer and volumetric lipid productivity were 9.31 g/L, 5.90 g/L and 0.082 g/L.h, respectively. Additionally, we determined the fatty acid composition of P. laurentii UFV-1 as follows: C14:0 (0.5%), C16:0 (28.4-29.4%), C16:1 (0.2%), C18:0 (9.5-11%), C18:1 (58.6-60.5%), and C20:0 (0.7-0.8%). Based on this composition, the predicted properties of biodiesel showed that P. laurentii UFV-1 oil is suitable for use as feedstock in biodiesel production.
RESUMO
O objetivo desse estudo foi verificar o dimorfismo sexual por meio de medidas lineares (Comprimento do corpo e processo odontóide, Comprimento do processo odontóide, Comprimento do forame vertebral, Largura do forame vertebral, Distância dos processos transversos, Distância do processo transverso esquerdo ao processo espinhoso, Distância do processo transverso direito ao processo espinhoso) da segunda vertebra cervical denominada de áxis. Para tanto foram analisadas 181 áxis, sendo 103 masculinas e 78 femininas, na faixa de idade de 22 a 85 anos, pertencentes ao "Biobanco Tomográfico e Osteológico Prof. Eduardo Daruge da FOP/UNICAMP". Tais medidas foram feitas pelo paquímetro digital marca Stainless hardned ® 150 mm Mauá São Paulo, Brasil, após a calibração inter e intraoperador realizada por meio do teste de correlação intraclasse, teve como resultado o valor de 0,98 considerado excelente. Verificou-se que todas as medidas estudadas são dimórficas e foi possível estabelecer um novo modelo de regressão logística, a partir dos dados obtidos junto às ossadas. Concluiu-se que o modelo de regressão logística gerado Germano Sexo = [- 22.7 + (0.16 × Comprimento do corpo) + (0.31 × Comprimento do forame vertebral) + (0.28 × Distância dos processos transversos)] possui 72,4 % de acerto.
The objective of this study was to verify the sexual dimorphism through linear measurements (length of the body and dentinoid process, length of the dentinoid process, length of the vertebral foramen, width of the vertebral foramen, distance of the transverse processes, distance from the left transverse process to the spinal process , Distance from the right transverse process to the spinous process) of the second cervical vertebra known as the Áxis. For this purpose, 181 Axioms were analyzed, of which 103 were male and 78 were female, in the age range of 22 to 85 years, belonging to the "Tomographic and Osteological Biobank Prof. Eduardo Daruge of FOP / UNICAMP ". These measurements were made by the stainless - hardned ® digital pachymetro 150 mm Mauá - São Paulo, Brazil, after the inter and intra - operator calibration performed through the intraclass correlation test, resulting in a value of 0.98 considered excellent. It was verified that all the measures studied are dimorphic and it was possible to establish a new model of logistic regression, based on the data obtained from the bones. It was concluded that the logistic regression model generated Germano Gender = [- 22.7 + (0.16 × Body length) + (0.31 × Vertebral foramen length) + (0.28 × Distance of transverse processes), with 72.4% of hit.