Session 26 - Environmental Biotechnology and Bioenergy

[CEST2019_00718] Thermal and kinetic analysis of biomass fuel (powders) by differential thermal gravimetric analysis (TGA/DTG/DTA)
by Kumar P., Subbarao P.M.V., Kala L.D., Vijay V.K.

The kinetics of the thermal decomposition of the agriculture residues were evaluated using a thermo-gravimetric analyser under non-isothermal conditions. The thermal behaviour and pyrolysis of two types of biomass i.e. pearl millet cob and eucalyptus by using TGA from ambient to 1000°C. Three different heating rates (10, 15, and 20°C/min) were taken for the thermogravimetric analysis. This study provides a basic insight into the Pearl Millet Cob pyrolysis, which can benefit our current work in developing advanced thermal processes for high-yield producer gas production from pearl millet cob waste.

Session: 26, Room: B, at Fri, 09/06/2019 - 13:39 to 13:42
Flash presentation in Environmental Biotechnology and Bioenergy
[CEST2019_00607] Lipid production by Rhodosporidium toruloides growing on media presenting composition similarities with the spent sulfite liquor in batch and fed-batch cultures
by Michou S., Vastaroucha E.-S., Sarris D., Kalantzi O., Papanikolaou S.

Aim of this study is to explore the effect of sodium lignosulfonate (SL), a paper industry by-product, on cell growth and lipid production by the yeast Rhodosporidium toruloides, cultivated on xylose-based media, that mimic the principal waste-stream originated from paper production facilities (viz. the spent-sulfite liquor). Yeast lipids present increasing interest as alternative non-food feedstocks for biodiesel production. Strains DSM 4444 and NRRL Y-27012 were shake-flask cultured under nitrogen-limiting conditions using xylose at 50 g/L, and SL was added at varying concentrations. Finally, a fed-batch bioreactor trial of the strain NRRL Y-27012 with optimum SL addition was carried out.
In the strain DSM 4444, maximum lipid production was obtained in media supplemented with 20 g/L SL, where lipid of 4.8 g/L occurred. In NRRL Y-27012 strain, maximum lipid production was seen with the addition of 10 g/L SL (lipid =5.3 g/L). In fed-batch bioreactor experiments carried out with the strain NRRL Y-27012, lipid =17.0 g/L (corresponding dry biomass =29.7 g/L) was achieved. The yield of lipid produced per unit of xylose consumed was ≈0.19 g/g. Lipids containing increased concentrations of oleic acid, constituting thus perfect materials amenable to be converted into “2nd generation” biodiesel were synthesized.

Session: 26, Room: B, at Fri, 09/06/2019 - 13:36 to 13:39
Flash presentation in Environmental Biotechnology and Bioenergy
[CEST2019_00610] Biotechnological production of polyols through conversions of crude glycerol by newly isolated strains of the yeast Yarrowia lipolytica
by Vastaroucha E.-S., Michou S., Kalantzi O., Papanikolaou S.

The purpose of this study is to investigate the ability of newly isolated Yarrowia lipolytica strains to grow on crude glycerol, the main by-product of the industrial production of biodiesel. In particular, the ability of the yeasts to metabolize glycerol and produce dry cell weight (DCW) and secondary metabolites such as lipid, endopolysaccharides and polyols (e.g. mannitol, arabitol, erythritol) was assessed. Two newly isolated strains (LMBF Y-46 and LMBF Y-47) were used, while trials were performed in different initial glycerol concentrations (Glol0=40-120 g/L) and various initial pH values (3.0-7.0) in shake-flasks. It has been seen that polyols production increased with decrease of pH value into the medium. At low Glol0 concentrations (=40 g/L), almost exclusively mannitol was synthesized (i.e. the strain LMBF Y-46 produced ~20 g/L of mannitol at pH=3.0). When Glol0 increased, other polyols (i.e. erythritol and arabitol) were also produced in appreciable quantities. At a pH=3.5 and for Glol0~120 g/L, a total quantity of polyols ~57 g/L was synthesized for the strain LMBF Y-46. Cellular lipids in restricted quantities (8-14% in DCW) were produced, while cellular polysaccharides increased with the time reaching to values of c. 35-42% w/w in DCW at the stationary phase of growth.

Session: 26, Room: B, at Fri, 09/06/2019 - 13:42 to 13:45
Flash presentation in Environmental Biotechnology and Bioenergy
[CEST2019_00593] LED light tailoring in a planar photobioreactor for optimization of microalgae growth.
by Riggio V.A., Occhipinti A., Grinic D., Zanetti M.

Microalgae are well known for their potential in producing valuable substances for nutraceutical and pharmaceutical industries, as well as a source of biofuel. The use of the photosynthetic capacity of microalgae is a new alternative for carbon dioxide bio-fixation. Therefore, the purpose of this work is to identify the best microalgae growth conditions, using an experimental planar photobioreactor (PBR) and LEDs with variable intensities as light source. Two different illumination intensity levels were used during the experiment: 33 and 57 µE of PPFD (Photosynthetic Photon Flux Density). A series of growth parameters such as temperature, pH, dissolved CO2 and oxygen concentrations, were real-time monitored. Optical density (OD) and dry weight were periodically evaluated in order to measure the concentration of biomass in the culture. Overall, the innovative approach of this work allowed to 1) successfully cultivate Scenedesmus obliquus in a closed photobioreactor under low photon flow; 2) establish a correlation between biomass concentration and LED intensity for this specific microalga strain which can be used in future experiments in order to finely tune light intensity to the desired biomass density.

Session: 26, Room: B, at Fri, 09/06/2019 - 13:15 to 13:30
Oral presentation in Environmental Biotechnology and Bioenergy
[CEST2019_00512] Biotechnological conversions of crude glycerol, residue deriving from biodiesel production facilities, by strains of the yeast Yarrowia lipolytica
by Papanikolaou S., Diamantopoulou P., Sarris D., Aggelis G.

Aim of the present study was to assess the ability of four Yarrowia lipolytica strains (ACA-DC 50109, LFMB Y-20, ATCC 20460 and LMBF Y-45) to grow on biodiesel-derived crude glycerol, the principal residue-stream deriving from biodiesel manufacture. Initial trials were carried out in shake-flasks under nitrogen limitation (initial glycerol Glol0~40 g/L, initial nitrogen ~0.35 g/L), that favor the production of cellular lipids and/or extra-cellular secondary metabolites like citric acid (CA). All strains produced appreciable dry cell weight (DCW) quantities (up to 13.0 g/L). The strain ACA-DC 50109 produced CA in concentrations up to 16.0 g/L, while lipid in DCW values of ~15% w/w were recorded. In the next stage, this strain was cultured on media with higher nitrogen limitation (Glol0~50 g/L, initial nitrogen ~0.15 g/L) in batch-bioreactor and shake-flask experiments, and comparable DCW (up to 8.0 g/L) and CA (25-28 g/L) quantities were reported for these trials. Lipid production was higher in the batch-bioreactor experiment. In fed-batch bioreactor trials performed thereafter, a maximum CA quantity of 66.1 g/L (conversion yield 0.66 g per g of glycerol) was obtained. Cellular lipids of all tested strains were mainly composed of the fatty acids Δ9C18:1, Δ9,12C18:2 and C16:0.

Session: 26, Room: B, at Fri, 09/06/2019 - 13:33 to 13:36
Flash presentation in Environmental Biotechnology and Bioenergy
[CEST2019_00368] Fuel performance of biodiesel from microalgae
by Cercado A.P., Ballesteros F., Capareda S.

Fuel performance of biodiesel produced from transesterification of microalgae was evaluated to assess its potential as alternative fuel in diesel engine. The biodiesel was produced from transesterification of microalgae Chlorella Vulgaris using K-pumice as catalyst. The engine used in the study was Yanmar 3009D, a small diesel engine with an output power rating of 14.2 kilowatts. The experiments showed comparable power and torque when the engine was run using both the commercial diesel and the algal biodiesel. Biodiesel from microalgae was able to establish a torque of equal to 45.5 N-m while commercial diesel had 48.25 at an engine speed of 2800 rpm. Net break power of Algal biodiesel and commercial diesel are 13.57kW and 13.50kW, respectively. Algal biodiesel had been found to have higher brake-specific fuel consumption and it has a lower exhaust concentrations of nitrogen oxides, oxides of carbon and total hydrocarbons when compared to the commercial diesel. Blending commercial diesel with concentration of algal biodiesel of up to 50% did not show significant change in the performance and emission of the commercial diesel.

Session: 26, Room: B, at Fri, 09/06/2019 - 13:00 to 13:15
Oral presentation in Environmental Biotechnology and Bioenergy
[CEST2019_00373] Cloning and sequencing of the gene encoding the enzyme for the reductive cleavage of diaryl ether bonds of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in Geobacillus thermodenitrificans UZO 3
by Suzuki Y., Nakamura M., Otsuka Y., Sato-Izawa K., Hishiyama S., Kameyama K., Kameyama T., Takahashi A., Katayama Y.

We have previously reported that a cell-free extract prepared from Geobacillus thermodenitrificans UZO 3 reductively cleaves diaryl ether bonds of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), a dioxin with the highest toxicity, in a sequential fashion producing 3’,4’,4,5-tetrachloro-2-hydroxydiphenyl ether (TCDE) as the intermediate, and 3,4-dichlorophenol (DCP) as the final reaction product. The detection of TCDE implicated the discovery of an unprecedented dioxin-degrading enzyme that reductively cleaves the diaryl ether bonds. In this study, we report the cloning and sequencing of the dioxin reductive etherase gene dreE which codes for the 2,3,7,8-TCDD-degrading enzyme. We showed that dreE was expressed in Escherichia coli and that the product of the expression could reductively cleave diaryl ether bonds of 2,3,7,8-TCDD to produce TCDE. Furthermore, we established that the amino acid sequence encoded by dreE was homologous to an enzyme with yet unknown function that is encoded by a gene located in the riboflavin (vitamin B2) biosynthesis operon in Bacillus subtilis. We also showed that the amino acid sequence possesses a coenzyme A (CoA) binding site that is conserved in the N-acyltransferase superfamily. For the first time, the degradation of 2,3,7,8-TCDD at the molecular level using a enzyme of bacterial origin has been demonstrated.

Session: 26, Room: B, at Fri, 09/06/2019 - 13:30 to 13:33
Flash presentation in Environmental Biotechnology and Bioenergy
[CEST2019_00278] Second generation bioethanol production from household food wastes via a newly isolated yeast strain of Wickerhamomyces anomalus
by Dazea D., Antonopoulou G., Alexandropoulou M., Ben Atitallah I., Mechichi T., Ntaikou I., Lyberatos G.

In the current study the efficiency of second generation bioethanol production from the pre-dried and shredded organic fraction of household food waste was investigated using the newly isolated yeast Wickerhamomyces anomalus X19. Separatete hydrolysis and fermentation (SHF) as well as simultaneous saccharification and fermentation (SSF) experiments were conducted at batch mode. Different loadings of cellulolytic enzymes as well as different mixtures of cellulolytic with amylolytic enzymatic blends were tested in order to enhance the substrate saccharification and conversion efficiency, leading to promising ethanol yields and productivities.

Session: 26, Room: B, at Fri, 09/06/2019 - 12:45 to 13:00
Oral presentation in Environmental Biotechnology and Bioenergy
[CEST2019_00222] Dairy wastewater as growth substrate for biomass and biocompound production by Spirulina platensis
by Escolà G., Zapata D., Aristizábal A., Arroyave C., Poschenrieder C., Llugany M.

Spirulina former Arthrospira is a Cyanobacteria with economic applications in agriculture, biofuel production and wastewater treatment. In this study the influence of the carbon source in the medium and the medium’s conductivity for Spirulina platensis UTEX growth over time was investigated. Three different culture media were evaluated: i) modified UTEX medium with inorganic carbon in the form of sodium bicarbonate and carbonate, ii) modified UTEX medium where inorganic carbon was replaced by lactic acid, and sea water enriched with lactic acid. Growth responses, morphological parameters (degree of spiralization), chlorophyll and phytohormone production were assessed.

Session: 26, Room: B, at Fri, 09/06/2019 - 12:30 to 12:45
Oral presentation in Environmental Biotechnology and Bioenergy