5 research outputs found
Biotecnologia e biomassa para o século XXI : estudo de meios de cultivo para a produção de biomassa de microalgas
Tese (doutorado)—Universidade de BrasÃlia, Programa em Rede Multi-Institucional do Pró-Centro-Oeste de Pós-Graduação em Biotecnologia e Biodiversidade, 2020.A biotecnologia e a produção biomassa são temas contemporâneos de grande relevância
mundial. Neste contexto, destacam-se as microalgas como fontes promissoras para a produção
de alimentos, bioprodutos e energia no século XXI. No entanto, existem diferentes desafios a
serem superados para tornar a produção indústrial de microalgas economicamente viável,
dentre eles o custo do meio de cultivo. Esta tese tem como objetivo apresentar duas
estratégias para a produção de biomassa de microalgas verdes (Chlorophyta) utilizando meios
de cultivo de baixo custo. A primeira estratégia consiste na formulação de meio quimicamente
definido que combina as fontes de nitrogênio (ureia, amônia e nitrato) com o uso de fertilizantes
como uma abordagem de baixo custo para o cultivo de Chlorella sorokiniana. O meio proposto
denominado "Blue Green Nitrogen Mix" (BGNIM), foi capaz de suportar o crescimento de C.
sorokiniana em nÃveis semelhantes ao meio sintético padrão BG11, apresentando
produtividades entre 47 e 50 mgDW • L-1
• d-1
. Adicionalmente, o uso combinado de três fontes
de nitrogênio levou a alterações na composição da biomassa. A concentração de proteÃnas
aumentou 7%, de carotenóides 41%, de açúcares solúveis 12%, alanina 370%, serina 350%,
valina 180%, mio-inositol 190%, ácido glicerico 230% e ácido glutâmico 220%, quando
comparado ao meio padrão BG11. Além disso, uma grande mudança de pH foi detectada
durante a fase inicial de crescimento em culturas de BGNIM, abrindo oportunidades para o
controle de predadores sensÃveis ao pH durante a produção em larga escala. É importante
ressaltar que a formulação BGNIM proporcionou uma redução de custo de aproximadamente
95% em comparação com o meio padrão BG11. A segunda estratégia foi a utilização de
efluente da indústria de óleo de palma (POME) como meio de cultivo algal quimicamente
indefinido. Neste trabalho, a linhagem autóctone de microalga Pseudokirchneriella sp. O LBA #
52. Esta foi selecionada dentre 18 linhagens testadas para crescimento em POME. A
produtividade da biomassa alcançou 272,13 mgDW • L-1
• d-1
durante o cultivo, usando
fotobiorreatores Flat Plate airlift de 15 L. Os carboidratos constituÃram a maior fração da
biomassa das algas, atingindo até 39,73%, enquanto a fração lipÃdica variou de 8,39% a
11,03% quando o POME é utilizado como meio de cultura. Além disso, o crescimento de algas
promoveu reduções de 61,21% do nitrogênio total (TN), 99,99% de amônio e 99,07% de fosfato
presentes no POME. Este estudo destaca o potencial do uso de microalgas no tratamento de
águas residuais e na produção de biomassa de alto valor agregado, integrada à indústria de
óleo de palma.Biotechnology and biomass production are contemporary themes of great worldwide relevance.
In this context, microalgae are highlighted as promising sources for the production of food,
bioproducts and energy in the 21st century. However, there are different challenges to be
overcome to make indústrial microalgae production economically viable, including the cost of
the medium. This thesis aims to present two strategies for the production of biomass from green
microalgae (Chlorophyta) using low cost cultivation media. The first strategy consists of
formulating a chemically defined medium that combines nitrogen sources (urea, ammonia and
nitrate) with the use of fertilizers as a low-cost approach to the cultivation of Chlorella
sorokiniana. The proposed medium called "Blue Green Nitrogen Mix" (BGNIM), was able to
support the growth of C. sorokiniana at levels similar to the standard synthetic medium BG11,
presenting productivity between 47 and 50 mgDW • L-1
• d-1
. Additionally, the combined use of
three nitrogen sources led to changes in the composition of the biomass. Protein concentration
increased 7%, carotenoids 41%, soluble sugars 12%, Alanine 370%, Serine 350%, Valine
180%, Myo-inositol 190%, Glyceric acid 230% and Glutamic acid 220%, when compared to
standard medium BG11. In addition, a large pH change was detected during the initial growth
phase in BGNIM cultures, opening up opportunities for the control of pH sensitive predators
during large-scale production. It is important to note that the BGNIM formulation provided a cost
reduction of approximately 95% compared to the standard BG11 medium. The second strategy
was to use effluent from the palm oil mill (POME) as a chemically indefinite algal culture
medium. In this work, the indigenous microalgae Pseudokirchneriella sp. LBA # 52 was selected
from 18 strains tested for growth in POME. Biomass productivity reached 272.13 mgDW • L-1
•
d
-1
during cultivation, using 15 L Flat Plate photobioreactors. Carbohydrates constituted the
largest fraction of algae biomass, reaching up to 39.73%, while lipid fraction varied from 8.39%
to 11.03% when POME is used as a culture medium. In addition, algae growth promoted
reductions of 61.21% of total nitrogen (TN), 99.99% of ammonium and 99.07% of phosphate
present in POME. This study highlights the potential of using microalgae in the treatment of
wastewater and in the production of high added value biomass, integrated with the palm oil
industry
Germination of Urochloa ruziziensis seeds according to substrate water availability and seeds moisture content
Water stress and seed water content can affect the first germination stages and disturb the full pasture establishment. This study aimed at evaluating the effect of substrate water availability and seed water content on the germination of Urochloa ruziziensis seeds, as well as verifying any harmful effect of seed imbibition. The treatments consisted of seeds with 9.5%, 11.3% and 14.6% of moisture content, subjected to substrate water availability simulated with aqueous solutions of polyethylene glycol 6000 (PEG 6000) of 0.0 MPa (PubMed control), -0.1 MPa, -0.2 MPa, -0.3 MPa and -0.4 MPa. The following characteristics were used to evaluate the seeds physiological quality: germination percentage and first counting, aerial and primary root length and seedlings fresh weight. The experimental design was completely randomized, with four replications of 50 seeds. All the evaluated characteristics were negatively influenced by the water potentials reduction, however, the U. ruziziensis seeds with 11.3% and 14.6% of moisture content showed a higher germination rate and seedlings growth at low water availability. Despite the reduction in the indexes evaluated for water deficiency, the damage extension in seeds was determined by seeds moisture content and water stress severity
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Biochemical and phylogenetic characterization of the wastewater tolerant Chlamydomonas biconvexa Embrapa|LBA40 strain cultivated in palm oil mill effluent.
The increasing demand for water, food and energy poses challenges for the world´s sustainability. Tropical palm oil is currently the major source of vegetable oil worldwide with a production that exceeds 55 million tons per year, while generating over 200 million tons of palm oil mill effluent (POME). It could potentially be used as a substrate for production of microalgal biomass though. In this study, the microalgal strain Chlamydomonas biconvexa Embrapa|LBA40, originally isolated from a sugarcane vinasse stabilization pond, was selected among 17 strains tested for growth in POME retrieved from anaerobic ponds of a palm oil industrial plant located within the Amazon rainforest region. During cultivation in POME, C. biconvexa Embrapa|LBA40 biomass productivity reached 190.60 mgDW • L-1 • d-1 using 15L airlift flat plate photobioreactors. Carbohydrates comprised the major fraction of algal biomass (31.96%), while the lipidic fraction reached up to 11.3% of dry mass. Reductions of 99% in ammonium and nitrite, as well as 98% reduction in phosphate present in POME were detected after 5 days of algal cultivation. This suggests that the aerobic pond stage, usually used in palm oil industrial plants to reduce POME inorganic load, could be substituted by high rate photobioreactors, significantly reducing the time and area requirements for wastewater treatment. In addition, the complete mitochondrial genome of C. biconvexa Embrapa|LBA40 strain was sequenced, revealing a compact mitogenome, with 15.98 kb in size, a total of 14 genes, of which 9 are protein coding genes. Phylogenetic analysis confirmed the strain taxonomic status within the Chlamydomonas genus, opening up opportunities for future genetic modification and molecular breeding programs in these species