Abstract Biomass production and bio-treatment of olive mill wastewater (OMW) were simultaneously achieved by cultivation of Scenedesmus sp. The influence of medium composition was addressed by analyzing the effect of the addition of unsterilized OMW (9% v·v − 1 ) and of inorganic nutrients, and the use of tap water. Performance of implemented treatments was assessed by analysis of the following variables: biomass productivity, growth rate, content of target microalgal fractions (lipids and carbohydrates), and consumption of OMW organic carbon fractions (reducing sugars and phenols). The addition of unsterilized OMW (9% v·v − 1 ) caused darkening of microalgal cultures inducing transition to heterotrophic growth. Growth rate values attained in heterotrophic cultures (with OMW) (0.0181 and 0.023 h − 1 ) were comparable to those attained in autotrophic cultures (without OMW) (0.0272 and 0.0249 h − 1 ). Nonetheless, significantly lower biomass productions were achieved by heterotrophic growth (0.22 and 0.35 g·L − 1 vs. 0.56 and 0.51 g·L − 1 ). Even though leading to lower biomass productions, heterotrophic growth ensured carbohydrate productions comparable to those attained by autotrophic growth (0.1 and 0.16 vs. 0.12 and 0.17 g·L − 1 ). Biodegradation of OMW phenols was found to be significantly affected by the concentration of inorganic nutrients. The inhibition of microalgal growth induced by phenols, and the interaction between phenol biodegradation and biomass production were analyzed.
Micro-algae have been recognized as a promising feedstock for biofuel production. Effective combining microalgae cultivation with wastewater treatment can reduce CO2 emissions and the cost of microalgae biofuel production, making it more feasible. However, the biomass and lipid productivity must be improved prior to large-scale production. The paper is therefore giving a critical review on microalgae productivity towards biofuel production focusing on the influencing factors in terms of strains ...
#1Benjamin Otto(Helmholtz Centre for Environmental Research - UFZ)H-Index: 3
#2Dietmar Schlosser(Helmholtz Centre for Environmental Research - UFZ)H-Index: 23
Main conclusion A green algal phenol oxidase was firstly purified, confirmed to be a laccase, and a hetero-oligomeric quaternary structure is suggested. The operation of a laccase-mediator system is firstly described in algae. Laccases (EC 1.10.3.2) catalyze the oxidation of a multitude of aromatic substrates. They are well known in higher plants and fungi, while their presence in green algae appears uncertain. Extracellular laccase-like enzyme activity has previously been described in culture s...
#1Wenguang Zhou(UMN: University of Minnesota)H-Index: 31
#2Paul Chen(UMN: University of Minnesota)H-Index: 63
Last. Roger Ruan(UMN: University of Minnesota)H-Index: 74
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The potential of algae-based biofuels to replace petroleum fuels and mitigate greenhouse gas production through microalgal photosynthesis has long been recognized. However, currently there are no commercial algae-to-fuels technologies that can overcome techno-economic barriers and address serious sustainability concerns. Coupling microalgae cultivation with wastewater treatment is considered as one of the most promising routes to produce bio-energy and bio-based byproducts in an economically via...
Abstract Using wastewater as resource for microalgal cultivation was seriously considered as a promising approach for sustainable biomass and lipid production. The proper selection of microalgal species is the foundation and key point to achieve this objective. This paper reviewed the recent status of microalgal cultivation in wastewater, including the characteristics of microalgal species used in recent studies, the performance of different microalgal species in different types of wastewater, t...
Background A major obstacle to the application of microalgae for bio-fuel production is light intensity reduction in high density cultures. Mixotrophic operation can solve this problem by exploiting the ability of microalgae to grow on organic carbon in dark conditions. In this article, mixotrophic growth of Nannochloropsis oculata and Chlorella vulgaris is analyzed. The influence of nitrate and glucose concentration on cell growth in 300 mL Erlenmeyer flasks was investigated using an experiment...
This purpose of the study was the development of a microalgal-bacterial consortium to degrade phenolic compounds. Two microalgae were isolated and characterized from an olive wash water (OWW) storage basin and identified as Scenedesmus obliquus and Chlorella vulgaris according to their 18S rRNA gene sequences. The two strains were cultured in synthetic olive washing water medium containing phenolic compounds, which showed they were capable of growth in the presence of these substances, although ...
Abstract The olive mill waste generated from olive oil extraction is a major environmental issue, particularly in Mediterranean areas. The extraction of olive oil is achieved through discontinuous or continuous processes. The two processes yield three fractions: a solid residue and two liquid phases (oil and olive mill wastewater). The characterization of these two by-products showed that they are mainly composed of phenolic compounds, carbohydrates, organic acids and mineral nutrients variably ...
One of the most important dilemmas of the modern world is to supply enough energy with minimal environmental impact. On this demand bioenergy from renewable biofuels is of growing public and private interest.
Abstract Micro-algae have received considerable interest as a potential feedstock for producing sustainable transport fuels (biofuels). The perceived benefits provide the underpinning rationale for much of the public support directed towards micro-algae research. Here we examine three aspects of micro-algae production that will ultimately determine the future economic viability and environmental sustainability: the energy and carbon balance , environmental impacts and production cost . This anal...
The mixture of olive-oil mill wastewater (OMW) and urban wastewater from secondary treatment (UWST) as culture medium was studied. Experiments were performed in a batch bioreactor on laboratory scale, using Scenedesmus obliquus CCAP 276/3A. In this sense, two experimental series were prepared. In the first, the culture medium was formed by 0%, 1%, 2.5%, 5%, 10% (v/v) of OMW added to UWST. In the second, a constant proportion (5% v/v) of bleached OMW was maintained and 0, 10, 25, and 50 (v/v) of ...
The decline in fishery resources from the wild has led to an ever increasing focus on aquaculture in recent years. With increasing aquaculture of animal species, there is an increasing need for suitable microalgae in the production of these animals. However, cultivation of microalgae in expensive pure chemical media is one of the major challenges facing large-scale cultivation of microalgae. The present study investigated the suitability of aquaculture wastewater (AWW) supplemented with NPK (nit...
Abstract The growth of bacteria contaminants can be controlled in heterotrophic microalgae cultures by using an uncoupled supply of glucose and nitrate. However, till now this strategy was only described for fed-batch cultivation. The cultivation in a sequencing batch reactor (SBR) could be more promising for the industrial scale. Here in this work, we tested the uncoupled supply of substrates on microalgae cultivated in SBR (feast/famine ratio = 1.33), with an optimized culture medium (based on...
Last. Sami Sayadi(Florida State University College of Arts and Sciences)H-Index: 75
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BACKGROUND The three-phase extraction process of olive oil produces highly contaminated wastewater (OMW). The elimination of this toxic by-product is an important environmental issue that requires the development of an appropriate management solution. Therefore, microalgae cultivation using OMW as growth medium was studied using single (the culture medium was formed by 0 to 80% OMUF or OMW added to BG11) and two-stage strategies (microalgae were firstly cultivated in the BG11 medium. In the seco...
This study assessed the feasibility of unhydrolyzed cogongrass as a medium fortificant for cultivation of Chlorella vulgaris UMT-M1 and Scenedesmus sp. KS-2. Nitrogen-limited media supplemented with 0.1–0.5% (w/v) cogongrass leaf extract induced changes in lipid content and produced effects that appear to counteract the effects of nitrogen depletion, restoring lipid and fatty acid content to levels similar to nitrogen-replete media while biomass was decreased. While nitrogen-limited media led to...
Last. Taeyoon Lee(Pukyong National University)H-Index: 9
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The purpose of this study was to investigate the optimum conditions of several factors (i.e., types and concentration of acetate, aeration rate, pH control) for maximizing the mixotrophic cultivati...
The olive mill wastewater harbors several natural products that are generally wasted in the environment without valorization. The polyphenols are the most predominant compounds found in olive mill wastewater exhibiting toxic effects of the ecosystems when they disposed at high concentrations. Therefore, green technology was recently used for the recovery of the valuable wasted compounds and their application in various industrial and medical applications. Hence, the bioremediation using microorg...
Abstract Microalgae cultivation processes are becoming increasingly used for food and feed production and for wastewaters treatment. Large part of laboratory experiments and industrial processes are carried out with microalgae cultivated in non-aseptic environments containing biological contaminants as bacteria, fungi, viruses and grazers. Such contaminants can significantly influence microalgae growth through interactions such as competition, parasitism, predation and mutualism. Accurate and se...
Gas-to-liquid (GTL) technology involves the conversion of natural gas into several liquid hydrocarbon products. The Fischer–Tropsch (F–T) process is the most widely applied approach for GTL, and it is the main source of wastewater in the GTL process. The wastewater is generally characterized by high chemical oxygen demand (COD) and total organic carbon (TOC) content due to the presence of alcohol, ketones and organic acids. The discharge of this highly contaminated wastewater without prior treat...
ABSTRACTA major constraint in the microalgal technology is the economics involved in cultivation and harvesting. This work is focussed on the optimization of nutrients for cultivation and harvestin...
Abstract An empirical model for prediction of microalgal growth in outdoor photobioreactors cultivation, using Principal Component Analysis (PCA) and Partial Least Squares (PLS) regression method, is implemented. Experimental data of biomass production were collected over 1 year of operation of a bubble column prototype, monitoring light and temperature and changing cultivation's conditions. PCA isolates 2 Principal Components that explain 80% of the variance and are associated with Environmenta...