Molecular characterisation ofBacilluschitinase for bioconversion of chitin waste

Abstract

In this work chitin was extracted chemically from shrimp shells. Seventeen Bacillus isolates were screened for chitinolytic activity. The chitinolytic strains of Bt. were screened at different temperatures and pHs for their hydrolytic potentials. By using a pair of specific primers, endochitinase gene was amplified from SBS Bt-5 strain through PCR, and then cloned into pTZ57 TA cloning vector and transferred in Escherichia coli DH5α strain. The sequenced gene (GenBank Accession No: HE995800) consists of 2031 nucleotides capable of encoding 676 residues. The protein consisted of three functional domains with a calculated molecular mass of 74.53 kDa and a pI value of 5.83. The amino acid sequence of chi gene showed 99% similarity to the genes of Bt MR11 endochitinase, Bt serovar kurstaki chitinase (kchi), Bt strain MR21 endochitinase and Bacillus cereus B4264.

Transcriptome analysis on the exoskeleton formation in early developmetal stages and reconstruction scenario in growth-moulting in Litopenaeus vannamei

“…For example, to produce 1 kilogram of chitosan from shrimp shells, more than 1 tonne of water is need and as well as a large amount of 40% sodium hydroxide solution. Thus, developing a natural way to degrade the waste shells will be promising and necessary 54, 55 . From our results, several chitin degradation-related genes with high expression in the moulting process could be targeted candidates.…”

Bacterial polyhydroxyalkanoates-eco-friendly next generation plastic: Production, biocompatibility, biodegradation, physical properties and applications

“…Further, there is diversity among bacteria from different ecological habitats in their PHA production, modes of growth, type of microorganisms and media ingredients. But, the most of standardization studies on PHA-producing bacteria, including Gram-negative and Gram-positive species, have reported the optimum pH 7 and incubation at 30-37°C for maximum yield (282)(283)(284)(285)(286)(287). Additionally, the biochemical and metabolic activities including the ability to utilize different carbon and nitrogen sources, and hydrolytic enzyme (amylase, lipase and protease) activities of bacterial candidates were also reported to play an important role in PHA synthesis.…”

Sustainable production with obtaining glucosamine from crab exoskeletons

“…Bacillus has been the source of a number of enzymes for different purposes, including chitinolytic activities (SALEEM et al, 2016), and is a consistent candidate for use in biotransformation methods.…”

“…Yet, this chemical method to hydrolysate chitin has the disadvantage whereby large amounts of acid solutions and other contaminants must be employed; therefore, it has been necessary to find alternative methods of extraction. This led to the use of enzymatic methods with individual enzymes involved or conjugated, such as pectinase, hemicellulase, cellulase, b-Dglucosaminidasas and even lipases, have proven exo-and endochitinase activity at different levels and various reaction conditions; fermentation methods have also been employed in the solid state with species of Bacillus, Serratia and Penicillium, where the action of certain enzymes mentioned before are utilized; these methods are friendly to the environment, relatively inexpensive and produce better yields than chemical methods (YALPANI et al, 1994;LEE et al, 2008;SUN et al, 2013;NIDHEESH et al, 2015;SALEEM et al, 2016). It is of interest to search for new enzymes, and combinations of them that are chitin degraders and obtain higher glucosamine yields than those currently obtained by particular research groups.…”