Extraction and Characterization of Chitin, Chitosan, and Protein Hydrolysate From the Invasive Pacific Blue Crab, Portunus Segnis (Forskål, 1775) Having Potential Biological Activities

The diversity of marine biomasses is a set of exploitable and renewable resources with application in several sectors. In this context, a co-culture based on three protease-producing bacterial isolates namely; Aeribacillus pallidus VP3, Lysinibacillus fusiformis C250R, and Anoxybacillus kamchatkensis M1V strains, was carried out in a medium based on the blue swimming crab Portunus segnis bio-waste. Proteases production was optimized using a central composite design (CCD). The highest level of proteases production obtained was 8,809 U/mL in a medium comprising 75 g/L of Portunus segnis by-product powder (Pspp). The biological value of Pspp and its obtained derivates were evidenced via accredited protocols. The recovered protein hydrolysate (PHyd) was found to be active towards radical scavenging power, and against angiotensin I-converting enzyme (ACE). The blue crab chitin (BC) extraction efficiency was achieved with a yield of 32%. Afterward, chitosan was prepared through chitin N-deacetylation with a yield of 52%, leading to an acetylation degree (AD) of 19% and solubility of 90%. In addition, chitosan is found to be active against the growth of all pathogenic bacteria tested.

Whole-Genome Sequence Data Analysis of Anoxybacillus kamchatkensis NASTPD13 Isolated from Hot Spring of Myagdi, Nepal

Anoxybacillus kamchatkensis NASTPD13 isolated from Paudwar hot spring of Myagdi, Nepal, upon morphological and biochemical analysis revealed to be Gram-positive, straight or slightly curved, rod-shaped, spore-forming, catalase, and oxidase-positive facultative anaerobes. It grows over a wide range of pH (5.0-11) and temperature (37-75°C), which showed growth in different reduced carbon sources such as starch raffinose, glucose, fructose, inositol, trehalose, sorbitol, mellobiose, and mannitol in aerobic conditions. Furthermore, the partial sequence obtained upon sequencing showed 99% sequence similarity in 16S rRNA gene sequence with A. kamchatkensis JW/VK-KG4 and was suggested to be Anoxybacillus kamchatkensis. Moreover, whole-genome analysis of NASTPD13 revealed 2,866,796 bp genome with a G+C content of 41.6%. Analysis of the genome revealed the presence of 102 RNA genes, which includes sequences coding for 19 rRNA and 79 tRNA genes. While the 16S rRNA gene sequence of strain NASTPD13 showed high similarity (>99%) to those of A. kamchatkensis JW/VK-KG4, RAST analysis of NASTPD13 genome suggested that A. kamchatkensis G10 is actually the closest neighbor in terms of sequence similarity. The genome annotation by RAST revealed various genes encoding glycoside hydrolases supporting that it can utilize several reduced carbon sources as observed and these genes could be important for carbohydrate-related industries. Xylanase pathway, particularly the genomic region encoding key enzymes for xylan depolymerization and xylose metabolism, further confirmed the presence of the complete gene in xylan metabolism. In addition, the complete xylose utilization gene locus analysis of NASTPD13 genome revealed all including D-xylose transport ATP-binding protein XylG and XylF, the xylose isomerase encoding gene XylA, and the gene XylB coding for a xylulokinase supported the fact that the isolate contains a complete set of genes related to xylan degradation, pentose transport, and metabolism. The results of the present study suggest that the isolated A. kamchatkensis NASTPD13 containing xylanase-producing genes could be useful in lignocellulosic biomass-utilizing industries where pentose polymers could also be utilized along with the hexose polymers.

Trends in valorization of the invasive crab Portunus segnis for cleaner production of chitin, chitosan, and protein hydrolysate

The diversity of marine biomasses is a set of exploitable and renewable resources with application in several sectors. In this context, a co-culture based on three protease-producing bacterial isolates namely; Aeribacillus pallidus VP3, Lysinibacillus fusiformis C250R , and Anoxybacillus kamchatkensis M1V strains, was carried out in a medium based on the invasive blue crab Portunus segnis bio-waste. Optimization of proteases production was performed using a central composite design (CCD). The highest level of proteases production obtained was 8,809 U/mL in a medium comprising 75 g/L of Portunus segnis by-product powder (Pspp ). The recovered protein hydrolysate (P Hyd ) was found to be active towards radical scavenging power, and against angiotensin I-converting enzyme (ACE). The extraction efficiency of the blue crab chitin (BC) was achieved with a yield of 32%. Afterward, chitosan was prepared through chitin N -deacetylation with a yield of 52%, leading to an acetylation degree (AD) of 19% and solubility of 90%. The spectrum of chitin and chitosan were depicted by Fourier-transform infrared spectroscopy (FTIR). The biological value of Pspp and its obtained derivates were evidenced via accredited protocols. These data constitute a roadmap towards a circular and sustainable bio-economic strategy for a clean transformation of a recalcitrant waste to bio-based products.

Draft Genome Sequence of the Thermophilic Bacterium Anoxybacillus kamchatkensis G10

ABSTRACTAnoxybacillus kamchatkensisG10 is a spore-forming thermophilic bacterium isolated from a hot spring in Indonesia. Here, we report the draft genome sequence ofA. kamchatkensisG10 that may reveal insights into aerobic/anaerobic metabolisms and carbon utilization in moderate thermophiles.