Agnese Cicci

Microalgal biomass production by using ultra- and nanofiltration membrane fractions of olive mill wastewater

Olive milling produces huge amounts of wastewater (OMWW) characterized by an extremely high organic load. Its polyphenols content is a hindrance to conventional biological treatment and to using it as growing medium for common microbial biomasses. The practice to dump it on soil is in conflict with the latest EU directives about waste management. OMWW can be effectively and efficiently treated by means of membrane technology to a fraction of the initial volume, but membrane processing concentrates still require treatment. Reversing the overall cost balance of membrane processing and subsequent treatment requires valorizing the concentrates through their reuse, as well as ensuring long-term service of the membrane system through effective wastewater pretreatment and sustainable, fouling-controlling, membrane operation conduite. Aim of this work is to reuse and valorize the ultra- and nanofiltration membrane concentrates as media for biomass production of microalgae and cyanobacteria. Scenedesmus dimorphus and Arthrospira platensis, usable as a food, feed, nutraceutical component or feedstock for biofuels, were selected for this investigation. Microalgal growth was experimentally determined and related to the composition of the concentrate-based media and to the irradiance distribution within the photobioreactor volume to decouple light limitation and medium chemical composition effects.

Fatty Acid Composition and Technological Quality of the Lipids Produced by the Microalga Scenedesmus Dimorphus 1237 as a Function of Culturing Conditions

Scendesmus dimorphus is an oleaginous eukaryotic microalga, able to produce and accumulate lipids up to a weight fraction of 49%. Aim of the present work is investigating the production of lipids by S. dimorphus 1237 and characterize them at a fatty-acid level. The variables accounted for were: the nutrient supply level and the extraction system (Soxhlet and bead beating). Two lipid phases were extracted by sequential, twin-solvent system (hexane and a chloroform:methanol mixture), the quantified gravimetrically and analyzed for their individual fatty acid composition by gas chromatography. The maximal total lipid concentration was measured by Soxhlet extraction in deficient nitrogen conditions (0.88 mg/L) and was found to be 49% (dw). In particular, palmitic acid was increased from 15% to 58% under phosphorous starvation and oleic acid content was increased from 8% to 40% under nitrogen starvation. Finally palmitic, palmitoleic and linolenic acid represented together more than 70% of the extracted lipids.

Analysis of microalgae growth in residual light: A diagnostics tool for low-cost alternative cultural media

Chapter 1 Most microalgae grow in photoautotrophy and some benefit from mixotrophy and their growth essentially depends on the effective available light intensity. Non transparent media are frequently obtained as the byproduct of bioprocessing but laboratory testing on the suitability of such media may provide misleading results even in laboratory scale photobioreactors. Chapter 2 Cicci et al. (2013) introduced the procedure for calculating a semi-empirical normalised growth rate accounting for a time-varying light limitation inside symmetric photobioreactors and permitting to cancel out the effects of unknown quantities in the photosynthetic response of the microalgal biomass and help diagnose the nutritional suitability of the composite medium. This paper presents the results of applying the semi-empirical normalised growth rate to microalgal growth experiments carried out on media obtained from an anaerobic cattle digestate and from an olive oil mill wastewater (OOMW) and discusses use, inherent opportunities of the proposed diagnostic tool.

Circular extraction: an innovative use of switchable solvents for the biomass biorefinery

The environmental impact of biomass processing can best be minimized by utilizing many components of the biomass and by getting maximum utility out of any solvent used. A Switchable-Hydrophilicity Solvent (SHS) has been used for a complete extraction of hydrophobic and hydrophilic molecules in the solvents opposite-hydrophilicity states, thus simplifying microalgal biomass extraction and increasing the solvent usefulness.

Adsorption of phenol/tyrosol from aqueous solutions on macro-reticular aromatic and macro-porous polystyrene cross-linked with divinylbenzene polymeric resins

Adsorption of Phenol/tyrosol from Aqueous Solutions on Macro-reticular Aromatic and Macro-porous Polystyrene Cross-linked with Divinylbenzene Polymeric Resins Jacques R. Njimou, Marco Stoller, Agnese Cicci, Angelo Chianese, Charles P. Nanseu-Njiki, Emmanuel Ngameni, Marco Bravi a Laboratory of Analytical Chemistry, Faculty of Sciences, University of Yaoundé 1, B.P. 812 Yaoundé, Cameroon b Department of Chemical Materials Environmental Engineering, Sapienza University of Rome, Via Eudossiana 18 – 00184, Rome, Italy njimoujacques@gmail.com, jacques_njimou@yahoo.it

Description of the biofouling phenomena affecting membranes by the boundary flux concept

Membrane fouling, showing up with a significant reduction of process productivity and membrane lifetime, is one of the main issues in membrane technologies and has been successfully described by the boundary flux concept. Although the concept was applied for both organic and inorganic fouling, biofouling enjoys partial treatises in literature. In this work, a model extending the boundary flux concept to biofouling issues was developed. A population dynamics-based model considering the development of a fouling layer originated by attached growing biomass on the surface of the membrane using nutrients and substrates available in the processed feed has been developed. The manuscript highlights the critical aspects of the developed model and the possible connection points between it and the boundary flux concept.

Mass Transfer, Light Pulsing and Hydrodynamic Stress Effects in Photobioreactor Development

Photobioreactor scalability involves multiple different interacting aspects including mass transfer, light pulsing and hydrodynamic stress. An efficient carbon dioxide supply and a frequent displacement of cells from poorly to highly illuminated zones is desired to maximise the achieveable specific growth rate. However, a strong mixing is energy consuming and may reduce the specific growth rate because of induced cell damage. The current work examines mass transfer effects in photobioreactor development and estimates their relationship to light pulsing and hydrodynamic stress effects with a special reference to the novel inclined, thinlayer, wavy-bottomed cascading photobioreactor.