Additionally, they have a wide spectrum of biological activities, such as anticancer [ 9 , 10 ], antituberculosis [ 11 , 12 ], anti-hepatitis C virus [ 13 ], and antibacterial [ 14 ] properties. Furthermore, the acid complexes with other metal ions are widely used in analytical chemistry, such as a reagent for gravimetric and spectrometric metals determination [ 15 ], as a chemical sensor in determination of metal ions [ 16 ], and as a reagent for removal of Acid Red 88 from textile wastewater [ 17 ].
On the basis of a literature review, it is evident that many studies have been carried out involving the production of HA from various feedstocks, which are now available as commercial products, however, the long chain HA have not been commercially available.
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They are widely used as surfactants in the pharmaceutical and soap industries [ 18 ]. Long chain HA are synthesized using fatty acids or vegetable oils as feedstock, in the presence of some enzymes. Fatty hydroxamic acids FHA , one of the derivatives of long chain HA, have been synthesized with the use of both edible and non-edible vegetable oils. The edible oils that have been used as a raw material for the synthesis of FHA are soybean oil [ 19 ] and palm oil [ 20 ].
Meanwhile, the non-edible oil that has been used for the synthesis of FHA is ketapang kernel oil [ 21 ]. According to Suhendra et al. In addition, the ketapang trees are widely distributed in Indonesia and are among the plants which bear fruits throughout the year.
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Their oil also has some characteristic physical-chemical properties. The formation of colored complexes between these metal ions and hydroxamic groups is a typical reaction Suhendra et al. This is a typical absorption band for amide. The nitrogen content of the product, which was determined using the Kjeldahl method, was 3.
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This is an indication that there are 2. Enzymes are biocatalysts produced by living organisms for the purpose of accelerating chemical reactions, by reducing activation energy, but remain unchanged at the end of the reactions. They are the most abundant group of proteins in living cells and when a protein is experiencing denaturation, they lose catalytic activity over time.
Some enzymes usually lose a large number of their catalytic activity during the incubation period. Hence, the effect of incubation time is a good indicator for enzyme performance and reaction progress. It pinpoints the shortest and most adequate time necessary to obtain good yields and minimize expenses [ 20 ].
This is in line with the result of the study conducted by Salwanee et al. This is due to the fact that the reaction catalyzed by the enzyme is reversible. The incubation time obtained from this study is faster than the results of Suhendra et al.
In terms of production cost, the substrate concentration must be as high as possible to get higher yields, however, the amount of enzyme in the reaction should be as low as possible in order to obtain maximum product yield per unit of enzyme. Increasing the amount of enzyme increases the rate of enzymatic reaction, until a limiting rate is reached, which is caused by more collisions between the enzyme and both the substrate and product molecules [ 21 ].
Generally, in all chemical reactions, an increase in temperature leads to an increase in the kinetic energy of the reacting molecules. Hence, there are more random collisions between the molecules per unit time, however, for enzymatic reactions, an increase in temperature also leads to an increase in the vibrational energy of the enzyme-substrate molecules.
Hydroxamic Acids: A Unique Family of Chemicals with Multiple Biological Activities
This is due to the fact that at the optimum temperature, the collision between the enzyme and substrate occurs very effectively, which causes the formation of an enzyme-substrate complex more easily. Additionally, according to [ 23 ], an increase in temperature increases the solubility of the substrate, thereby making available more substrates for the enzymatic reactions.
This is due to the fact that at high temperatures, the active site of the enzyme changes shape, making it less complementary to the shape of the substrate, hence, its ability to catalyze is reduced.
Finally, the enzyme is denatured and no longer functions [ 24 ]. The reaction conditions were 20 g of oil, mmol of N-methylhydroxylamine, mL of hexane, 0. All the chemicals and reagents were purchased from commercial suppliers and used as received. The extraction of oil from the ketapang seeds was carried out using the modified method developed by Suhendra et al. First, the seeds were mashed and about 10 g were put into the Soxhlet extraction thimble and extracted with mL of n -hexane for 6 h.
The synthesis of N-MFHA from ketapang seed oil, in general, followed the modified procedures developed by Suhendra et al. This involved the addition of some ketapang oil with 15 mL of hexane in a mL closed Erlenmeyer. Then, N -methylhydroxylamine hydrochloride, neutralized using 6 M NaOH, was added at a certain concentration.
The qualitative analysis of the HA group was conducted using several modifications of the procedures developed by Suhendra et al. The quantitative analysis of the product was conducted by determining its nitrogen content using the Kjeldahl method. The analysis was carried out using acetonitrile as eluent at a flow rate of 1. This study investigated the synthesis of N -methyl fatty hydroxamic acids from ketapang seed oil using the lipase-active biocatalyst Lipozyme TL IM. Book Review. Read the full text. Tools Request permission Export citation Add to favorites Track citation.
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