Browsing by Author "Tonova, Konstantza"

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Extraction by ionic liquids for the case of detoxification of lignocellulosic hydrolysates
(Royal Society of Chemistry, 2024-07) Tonova, Konstantza; Zhivkova, Svetlana; Lazarova, Madlena; Mustafa, Ahmad
This study deals with hydrophobic phosphonium ionic liquids (ILs), phosphinate and neodecanoate, used in liquid-liquid extraction for the purpose of complex detoxification of lignocellulosic hydrolysates from inhibitors, whilst preserving the sugar content. The topic is considered from two aspects, a theoretical one in which extraction from a model multicomponent solution composed of acids, furan, phenolics, and sugars is investigated, and practically by employing a real rice straw hydrolysate. Using the model solution in cross-current extraction mode, the main process parameters, pH and concentration of the ILs, are studied. The extraction mechanisms of acids (sulfuric, gallic, acetic and levulinic acids) and aldehydes (vanillin and furfural) are established. Extraction of the acids in both ILs proceeds by a competitive mechanism until the two reactive H-bonding sites located at the two oxygen atoms in the IL's anion are occupied. In addition to H-bonding, extraction of the phenolic acid is substantially assisted by hydrophobic interactions, while the sulfuric acid is readily extracted by protonation of the IL's anion. An above-stoichiometric extraction of acids by phosphonium phosphinate has been found, which occurs by acid-acid H-bonds between phenolic and organic acids. Co-extraction between phenolic acid and phenolic and furanic aldehydes is observed which is based on the H-bonds that exist in acidic media and the staking interactions of the aromatic rings. The extraction of real rice straw hydrolysate carried out in three runs reaches a high removal of organic acids (over 63%), furans (over 80%) and phenolic compounds (over 97%) in each run.
Has the time finally come for green oleochemicals and biodiesel production using large-scale enzyme technologies? Current status and new developments
(Elsevier Inc., 2023-10) Mustafa, Ahmad; Faisal, Shah; Ahmed, Inas A; Munir, Mamoona; Cipolatti, Eliane Pereira; Manoel, Evelin Andrade; Pastore, Carlo; di Bitonto, Luigi; Hanelt, Dieter; Nitbani, Febri Odel; El-Bahy, Zeinhom M; Inayat, Abrar; Abdellatief, Tamer M.M; Tonova, Konstantza; Bokhari, Awais; Abomohra, Abdelfatah
With the growth of the chemical industry over the last decade, the need for cheaper (and more environmentally friendly) alternatives to petrochemicals of ever-increasing cost has grown steadily. Oleochemicals and biodiesel (OC/BD) are considered as green alternatives to petroleum derivatives, because they come from renewable oils and fats. OC/BD are currently produced by the traditional energy intensive chemical catalyzed methods, which have several economic and environmental drawbacks. For these reasons, the enzymatic production of OC/BD has attracted a growing attention for their greener pathway with respect to the chemically catalyzed processes. Lipase-catalyzed processes have a low energy requirement, since reactions are performed under atmospheric pressure and mild temperature and without the creation of side reactions. Furthermore, utilization of enzyme catalysts offers many advantages such as reducing the initial capital investment due to simplified downstream processing steps. Despite all the previous advantages, however, the high cost of lipases restricted their large-scale utilization. In the past decade, efforts have been made to reduce the cost of the enzymatic-catalyzed synthesis of OC/BD. However, most previous studies have studied only the technical feasibility of the lipase-catalyzed re- actions and overlocked the economic viability. This review critically discusses the factors affecting the promotion of the economic feasibility of the enzymatic processes from the lab to large scale. These include reactor configuration, type of feedstock, conditions optimization, immobilization, lipase-producing microorganisms
Has the time finally come for green oleochemicals and biodiesel production using large-scale enzyme technologies? Current status and new developments
(Elsevier Inc, 2023-12) Mustafa, Ahmad; Faisal, Shah; Ahmed, Inas A; Munir, Mamoona; Cipolatti, Eliane Pereira; Manoel, Evelin Andrade; Pastore, Carlo; Bitonto, Luigi di; Hanelt, Dieter; Nitbani, Febri Odel; El-Bahy, Zeinhom M; Inayat, Abrar; Abdellatief, Tamer M.M; Tonova, Konstantza; Bokhari, Awais; Abomohra, Abdelfatah
With the growth of the chemical industry over the last decade, the need for cheaper (and more environmentally friendly) alternatives to petrochemicals of ever-increasing cost has grown steadily. Oleochemicals and biodiesel (OC/BD) are considered as green alternatives to petroleum derivatives, because they come from renewable oils and fats. OC/BD are currently produced by the traditional energy intensive chemical catalyzed methods, which have several economic and environmental drawbacks. For these reasons, the enzymatic production of OC/BD has attracted a growing attention for their greener pathway with respect to the chemically catalyzed processes. Lipase-catalyzed processes have a low energy requirement, since reactions are performed under atmospheric pressure and mild temperature and without the creation of side reactions. Furthermore, utilization of enzyme catalysts offers many advantages such as reducing the initial capital investment due to simplified downstream processing steps. Despite all the previous advantages, however, the high cost of lipases restricted their large-scale utilization. In the past decade, efforts have been made to reduce the cost of the enzymatic-catalyzed synthesis of OC/BD. However, most previous studies have studied only the technical feasibility of the lipase-catalyzed reactions and overlocked the economic viability. This review critically discusses the factors affecting the promotion of the economic feasibility of the enzymatic processes from the lab to large scale. These include reactor configuration, type of feedstock, conditions optimization, immobilization, lipase-producing microorganisms.