Evaluation of the catalytic activity of lipases immobilized on chrysotile for esterification

Our plain-English summary of Evaluation of the catalytic activity of lipases immobilized on chrysotile for esterification, by J.E. Silva, P.C. Jesus (Anais Da Academia Brasileira de Ciências, 2003).

The study

• Authors: J.E. Silva, P.C. Jesus
• Journal: Anais Da Academia Brasileira de Ciências
• Published: 2003;75(2):157-62
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

In the present work, the ester synthesis in organic media catalyzed by lipases immobilized on chrysotile was studied. Lipases of different sources (Mucor javanicus, Pseudomonas cepacia, Rhizopus oryzae, Aspergillus niger and Candida rugosa) were immobilized on chrysotile, an inexpensive magnesium silicate, and used for esterification of hexanoic, octanoic and lauric acid with methanol, ethanol, 1-butanol and 1-octanol at 25 C in hexane as solvent. The best results were obtained with Mucor javanicus lipase and lauric acid giving yields of 62-97% of ester.

In plain English

This was a laboratory chemistry study. It did not study people, asbestos exposure or health. The authors used chrysotile, which they called one of the main asbestos sources, as a solid support for enzymes called lipases. Five lipases, from Mucor javanicus, Pseudomonas cepacia, Rhizopus oryzae, Aspergillus niger and Candida rugosa, were attached to chrysotile. They were used to make esters from fatty acids and alcohols in hexane at 25°C. Chrysotile took up 70% of the lipase, except for Aspergillus niger lipase at 30%. That lipase produced too little ester to measure. With Mucor javanicus lipase, lauric acid gave ester yields from 62% to 97%. Chrysotile without enzyme produced no ester. When lauric acid and 1-butanol were reacted using free lipases in hexane for 48 hours at 25°C, no product formed. In a reuse test making n-pentyl laurate from lauric acid and 1-pentanol, the Mucor javanicus preparation gave yields of 82%, 80%, 25% and 24% over four uses. The authors concluded that chrysotile with adsorbed lipases is a very attractive and viable alternative for enzyme reactions in organic solvents.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: laboratory chemistry experiment (enzymes immobilized on chrysotile and tested for ester synthesis, with control reactions); no human or animal subjects
• Who was studied: No people or animals. Five commercial lipases (from Pseudomonas cepacia, Candida rugosa, Aspergillus niger, Mucor javanicus and Rhizopus oryzae), immobilized on chrysotile type 5RL from the SAMA'S mine in Goiás, Brazil
• Exposure: Chrysotile asbestos used only as a support material for enzymes in laboratory reactions; no human exposure was studied
• Main results:
  • Chrysotile adsorbed 70% of the lipase, except Aspergillus niger lipase
  • Only 30% of Aspergillus niger lipase was immobilized, and its ester yields could not be determined because too little ester formed
  • With Mucor javanicus lipase on chrysotile, lauric acid gave the best yields, from 62% to 97%
  • The authors found Mucor javanicus lipase more efficient than the other lipases when immobilized on chrysotile
  • Chrysotile without enzyme produced no reaction
  • When the reaction of lauric acid and 1-butanol was repeated using free (non-immobilized) lipases in hexane for 48 hours at 25°C, no product formed
  • On reuse of Mucor javanicus lipase on chrysotile in the reaction of 1-pentanol with lauric acid, n-pentyl laurate yields were 82%, 80%, 25% and 24% for uses 1 to 4
  • The n-pentyl laurate yield with Mucor javanicus lipase varied by solvent: 82% in hexane, 70% in cyclohexane, 68% in toluene, and no ester in dichloromethane, acetone or acetonitrile
• The authors' conclusion: The authors concluded that chrysotile with adsorbed lipases is a very attractive and viable alternative for enzymatic reactions in organic media

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Chrysotile, Silicate.

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