engleski

Employment of amylase in direct production of lactic acid: mining alpha-amylases from Lactobacillus sp.

Implementation of novel whole-cell catalyzed bioprocesses is considered as a key technology for conversion of renewable raw materials into biochemical(s). The microbial cells which synthesize so called critical enzymes (e.g. amylase, protease) have attracted special attention because they can be employed in direct conversion of the renewables within sustainable industrial-scale production. By their application conventional metabolic frame, intracellular metabolism of simpler substrates, can be connected to balanced extracellular degradation of polymeric substrates and considerably expanded. In the case of lactic acid bacteria (LAB) which produce at least one of the critical enzymes - amylase, it means that traditional fermentative industrial production of lactic acid (LA) can be expanded into amylolytic-fermentative bioprocesses. Amylolytic LAB (ALAB) Lactobacillus amylovorus DSM 20531T was used as a potent biocatalyst which possesses interdependent amylolytic-fermentative activity and it carried out highly efficient direct conversion of starch-containing renewable raw material to LA. Raw-starch binding alpha-amylase was produced by the ALAB in submerged fermentations and semi-solid substrate saccharification and fermentation [1]. The enzyme produced by L. amylovorus strains was only partially characterized [1-4]. Basic characteristics (reaction type, amino acid sequence, stability, etc.) of the enzyme have not yet been determined (BRaunschweig ENzyme DAtabase, http://www.brenda-enzymes.org). Amino acid sequence of forty alpha-amylases (EC 3.2.1.1) from genus Lactobacillus was accessed (2013-06-13) via The National Center for Biotechnology Information (NCBI, http://www.ncbi.nlm.nih.gov) and compared by using Vector NTI® Express Software (http://www.invitrogen.com). Mining the alpha-amylases from Lactobacillus sp. represents key step in routing further investigation and application of novel biocatalysts in direct production of the LA from the renewables.

lactic acid; direct production; amylase; Lactobacillus sp.

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