Molecular genetic analysis of a 2-haloacid halidohydrolase structural gene

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Molecular biology of the 2-haloacid halidohydrolase IVa from Pseudomonas cepacia MBA4

The structural gene (hdl IVa) for the Pseudomonas cepacia MBA4 2-haloacid halidohydrolase IVa (Hdl IVa) was isolated on a 1.6kb fragment of Ps. cepacia MBA4 chromosomal DNA. The recombinant halidohydrolase was expressed in Escherichia coli and Pseudomonas putida and the structural gene was subcloned on to the tac expression vector pBTac1. High-level expression from the tac promoter was seen to be temperature-dependent, a consequence of the nucleotide sequence adjacent to the fragment encoding the halidohydrolase. The nucleotide sequence of the fragment encoding the Hdl IVa was determined and analysed. Three ATG codons were identified in one of the open reading frames and the one corresponding to the start of the hdl IVa structural gene was determined by comparison of the predicted amino acid sequences with the experimentally determined N-terminal sequences of halidohydrolase IVa. The hdl IVa gene encoded a 231 amino acid-residue protein of M(r) 25 900. The sequence and predicted structural data are discussed and comparison is made with sequence data for other halidohydrolases.link_to_subscribed_fulltex

Studi Komparasi: Produksi Bioetanol Nira Batang Kelapa Sawit oleh Flokulan dan Non- Flokulan Saccharomyces Cerevisiae

Two types of yeast were used for bioethanol production from oil palm trunk sap, the flocculant Saccharomyces cerevisiae NCYC­1195 and non­flocculant Saccharomyces cerevisiae Kyokai 7 (NCYC-479). Flocculant Saccharomyces cerevisiae is yeast that has ability to aggregate into flocks which precipitate rapidly in culture medium. The effect of urea as a nitrogen source was also investigated in this study. Some concentrations of urea were added i.e. 0%, 0.1%, 0.2%, and 0.3% (w/v) during fermentation. The purpose of this study is to obtain the best condition by strain of Saccharomyces cerevisiae and urea concentration for the highest ethanol production. The highest ethanol production and yield was obtained at 4.86% (v/v) and 0.52 (g/g) respectively, by nonflocculant Saccharomyces cerevisiae Kyokai 7 (NCYC-479) without the addition of urea