Environmental Biotechnology and Bioenergy

The co-pyrolysis of lignocellulosic wastes such as Corn stover with plastic has been found to improve the both the yield and quality of pyrolysis oil and gas products. In this study, the co-pyrolysis of Corn stover (CS) with plastic (LDPE, and PP) were studied through thermogravimetric analysis. The parameter “change in weight loss rate” denoted by ΔW was used to quantify the synergistic effects on the yield during co-pyrolysis. The ΔW values were fitted using a combined mixture design to generate an RSM model relating the factors mixture component proportions, plastic type, and temperature to the response ΔW. From numerical optimization, the obtained optimum co-pyrolysis conditions are: (a) 0.60 CS proportion, 0.40 LDPE proportion, and 481.73 ℃ temperature for CS-LDPE, (b) 0.68 CS proportion, 0.32 PP proportion, and 492.15 ℃ temperature for CS-PP. The activation energy, and pre-exponential factor of the reactions in the co-pyrolysis process were also obtained using direct solution method. The activation energy of the reaction that took place from 420 to 510 ℃ was found to be lower in the co-pyrolysis of Corn stover and plastic than in the pyrolysis of pure plastic.

Session: 32, Room: B, at Fri, 09/06/2019 - 16:27 to 16:30
Flash presentation in Environmental Biotechnology and Bioenergy

The effect of base leaching on pure silica ITQ-29 zeolite being the counterpart of LTA zeolite, was investigated. The extent of the desilication process over pure silica zeolite was controlled by partial detemplation followed by silicon extraction. The potential of hierarchically porous ITQ-29 zeolite in environmentally friendly applications concern selective adsorption of organic molecules in aqueous environments. The introduction of additional porosity by desilication process offers full usage of zeolite grains volume without diffusional limitations during the adsorption process.

Session: 32, Room: B, at Fri, 09/06/2019 - 16:21 to 16:24
Flash presentation in Environmental Biotechnology and Bioenergy

Volatile Organic Compounds (VOCs) are toxic for the environment and human health and their tendency to readily volatilize in the atmosphere leads to problems connected to odours annoyance. The conventional treatments for VOCs gaseous emissions conventionally entail the application of chemical-physical processes, only promoting the transfer of the contaminants from gas to liquid and/or solid phases. Advanced Oxidation Process (AOPs) and biological processes, conversely, support the oxidation of the organic pollutants, promoting their conversion into harmless and odourless compounds.
This study aims at evaluating the performance of an innovative treatment solution, at pilot scale, of AOPs pretreatment coupled with a bio-scrubbing unit for the abatement of toluene, selected as model VOCs. Different operating conditions have been evaluated to understand the behavior towards inlet load fluctuations.
The results exhibited that the ozonation applied as pretreatment to the biological process may promote an increase of the pollutant biodegradability along with synergic effects due to the absorption of the ozone derived compounds into the culture growth, resulting in a significant enhancement of removal performances respect to the conventional biotechnologies.

Session: 32, Room: B, at Fri, 09/06/2019 - 15:45 to 16:00
Oral presentation in Environmental Biotechnology and Bioenergy

The heterotrophic growth of C. vulgaris using crude glycerol as the sole carbon source was studied in five 5L flasks. Air in each flask was provided at a rate of 300 L/hr and the contents were continuously stirred with a magnetic bar. Temperature, pH and initial inorganic nutrients (nitrogen, phosphorus, potassium and micronutrients) were kept the same in all flasks. The C/N ratio varied in each of the five flasks was set at 6, 13, 25.4, 61.5 and 118 respectively while the nitrogen initial concentration was equal to 45.4 mg/L in all flasks. The residual organic carbon was measured as a function of cultivation time. It was found that biomass growth rates as well the lipid and protein content were dependent on the C/N ratio. Lipid content was proportional to the C/N ratio while the protein content was inversely proportional to the C/N ratio. Carbon concentrations above 2500 mg/L inhibited the growth rate.

Session: 32, Room: B, at Fri, 09/06/2019 - 16:15 to 16:18
Flash presentation in Environmental Biotechnology and Bioenergy

Pyrolysis of Spirulina sp. Microalgae was carried out in a semi-batch glass reactor system. Effect of temperature on the yields of pyrolytic products (gaseous, liquid and solid residue) and chemical composition of the liquid products were investigated. All experiments were performed in 25 mL/min nitrogen atmosphere with 15 g feedstock which was dry and powder form of Spirulina. Temperature was varied from 470 to 620 °C with 50 °C break by utilizing PID controller which was setted 10 °C/min heating rate. The aqueous phase and bio-oil (organic phase) of the liquid products were characterized by GC-MS. Maximum yields of bio-oil and aqueous phase were obtained approximately as 30 wt. % at 520 °C and as 20 wt. % at 470 °C. When temperature was increased, oxygenated compounds and aromatic hydrocarbons decreased. However, nitrogenous compounds and alkanes increased in the microalgal pyrolytic bio-oil.

Session: 32, Room: B, at Fri, 09/06/2019 - 16:00 to 16:15
Oral presentation in Environmental Biotechnology and Bioenergy

Long chain fatty acids are major lipid constituents. In this study, anaerobic digestion of oleic, palmitic or stearic acid (5 g/L each) emulsified with whey protein (20 g/L) was examined in continuous (batch-fed) stirred tank digesters with 2 L working volume. Anaerobic co-digestion of oleic acid displayed high biogas yield (0.47 L/gCOD), compared to palmitic (0.42 L/gCOD) and stearic acid (0.30 L/gCOD). Oleic acid, despite its high biodegradability resulted in major inhibition of the acetoclastic methanogens, as demonstrated by VFA accumulation and by the methanogenic activity assay. Biogas production from palmitic acid was stable, with a biogas yield close (90%) to the theoretically expected values. This was not the case however for stearic which displayed negligible biodegradability. Application of the ADM1 revealed the maximum degradation rate constant of each LCFA. Based on the results of this study it can be concluded that stearic acid degradation is the rate limiting step of the anaerobic digestion process, and this attributed to its low solubility and thus bioavailability.

Session: 32, Room: B, at Fri, 09/06/2019 - 15:15 to 15:30
Oral presentation in Environmental Biotechnology and Bioenergy

Screened dairy manure, pressure-sterilized animal by-products, and cheese whey were co-digested in a Plug Flow Reactor (PFR) over a period of 150 days. The PFR process was stable even under a hydraulic retention time of 3 days, corresponding to an organic loading rate (OLR) of 22 g/Ld. Effluent COD remained low (5.6±1.4 g/L) while VFA concentrations were negligible (< 0.5 g/L as COD). The biogas production rate from the PFR ranged from 2.6 up to 7.3 L/Ld. The anaerobic digestate was characterized by high ammonia content (1.7±0.5 g/L); therefore air-stripping was chosen for the effective removal of ammonia. Hydrated lime as a slurry was utilized for the necessary pre-treatment step (pH-raising), due to its fast reaction and low cost. A temperature of ≥ 45 °C was also needed for efficient ammonia removal. The final effluent was neutralized by CO2 absorption through biogas injection in a scrubber. Concurrently, the biogas was upgraded since its methane content increased substantially, while H2S was completely removed.

Session: 32, Room: B, at Fri, 09/06/2019 - 15:30 to 15:45
Oral presentation in Environmental Biotechnology and Bioenergy

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

Iron deficiency is one of the main causes of chlorosis in plants, which leads to the loss in the field crops quality and yield. Iron-deficiency is a worldwide problem, particularly sever in calcareous soils (about 30% of world´s land surface). The current use of synthetic iron-chelates to prevent or correct iron-deficiency in plants raises environmental concerns due to their poor biodegradability. Thus, new, more environmentally-friendly efficient solutions are needed to solve iron deficiency-induced chlorosis (IDIC) in crops grown in calcareous soils. In this work, a new green freeze-dried iron fertilizer was produced (patent submitted) from a culture of A. vinelandii containing siderophores of a natural source able to bind iron at pH 9. Soybean plants cultivated under calcareous soils and treated with the green iron-fertilizer responded more significantly and comparable to the positive control, ethylenediaminedi(o-hydroxyphenylacetic) acid, than those treated with the negative control, when evaluated by their growth (dry mass) and chlorophyll concentration (SPAD index). On average, iron content was also greater on green iron-fertilizer treated plants than on negative control treated ones. Results suggest that the freeze-dried product, prepared from A. vinelandii culture, can be a viable alternative for mending IDIC of soybean plants grown in calcareous soils.

Session: 32, Room: B, at Fri, 09/06/2019 - 15:00 to 15:15
Oral presentation in Environmental Biotechnology and Bioenergy

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

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

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

The ability of several strains belonging to Pleurotus ostreatus and P. eryngii mushroom genera to grow on various agricultural residues was examined and their mycelium growth rates and biomass production (estimated as glucosamine content) were compared. Four P. ostreatus (AMRL 137, 144, 147, 150) and four P. eryngii (AMRL 160, 163, 166, 173-6) strains were cultivated on wheat, barley and oat straw, poplar and beech-wood sawdust, cotton and coffee residues, corn-cobs, rice bark, olive cake supplemented with wheat bran on a final C/N 20-30. Colonization rate measurements of mycelium demonstrated faster colonization on wheat, beech, barley and oat, corn-cobs and rice with values of ~1.5 mm/day, yet the faster colonizers were P. ostreatus 144, 150 and P. eryngii 166, 173-6. Glucosamine content was similar for P. ostreatus and P. eryngii strains and the most pronouncing substrates for more biomass production were barley and oat straw, beech-wood sawdust, cotton and coffee residues, corn-cobs (max 450 mg/g d.w.). However, in most of the cases, glucosamine content was opposite to mycelial growth rate, as strains with high colonization rates produced the least biomass. These results are evaluated in the view of bio-converting agricultural wastes into mushrooms, an added value food with medicinal properties.

Session: 32, Room: B, at Fri, 09/06/2019 - 16:24 to 16:27
Flash presentation in Environmental Biotechnology and Bioenergy

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

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

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

This work determined the effects of enzyme treatment on the mechanical properties of natural fiber-reinforced composite using Pandanus simplex (karagumoy) fibers. Physical modification using enzyme improved chemical and mechanical properties of fibers and the karagumoy fiber-reinforced composites (KFRCs) produced. Enzyme concentration and soaking time were used as treatment parameters. The treatment scheme improved the mechanical properties of fibers and composites, as well as, the composites’ water absorption property. The composites’ mechanical properties- tensile and flexural strength- were measured using universal testing machine (UTM). The morphology of fibers and composites was determined through a scanning electron microscope (SEM) and results indicated a reduced fiber diameter for the treated fibers and an increase in fiber surface roughness, thereby resulting to improved adhesion or compatibility between the hydrophilic fiber and the hydrophobic matrix. FTIR analysis results of the fibers further supported this finding as evidenced by the reduction in OH groups of the enzyme-treated karagumoy fibers.

Session: 32, Room: B, at Fri, 09/06/2019 - 16:18 to 16:21
Flash presentation in Environmental Biotechnology and Bioenergy

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

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