purification-identification-antimicrobial-protein-from-green-alga

Purification and Identification of Antimicrobial Protein from the Green Alga <em>Tetraspora</em> Sp. CU2551

Antimicrobial resistance (AMR) is an escalating global health threat, necessitating the discovery of novel antimicrobial agents. Algae-derived proteins ...

Rajamangala University of Technology Thanyaburi

Synechocystis sp. PCC 6803 strains overexpressing pha genes were constructed and characterized for poly-3-hydroxybutyrate (PHB) production. These pha overexpressing strains showed slightly reduced growth rates. Under N-deprived condition, the strains overexpressing (OE) phaAB, phaEC and phaABEC showed significantly higher PHB contents than the wild type. The maximum PHB content, a 2.6-fold increase producing 26% PHB (dcw), was observed in OE phaAB cells grown for 9days in N-deprived medium. Under this condition, these OE phaAB cells increased PHB production to 35% PHB (dcw) upon addition of 0.4% (w/v) acetate. Higher PHB granules in OE phaAB cells were clearly visualized by both Nile red staining and TEM imaging. All OE strains under N-deficient condition had increased glgX transcript levels. Overall results demonstrate an enhanced PHB production in Synechocystis cells overexpressing pha genes, particularly phaA and phaB, when grown in N-deprived medium containing 0.4% (w/v) acetate.

Enhancement of poly-3-hydroxybutyrate production in Synechocystis sp. PCC 6803 by overexpression of its native biosynthetic genes.

Bio-hydrogen from microalgae including cyanobacteria has attracted commercial awareness due to its potential as an alternative, reliable and renewable energy source. Photosynthetic hydrogen production from microalgae can be interesting and promising options for clean energy. Advances in hydrogen-fuel-cell technology may attest an eco-friendly way of biofuel production, since, the use of H to generate electricity releases only water as a by-product. Progress in genetic/metabolic engineering may significantly enhance the photobiological hydrogen production from microalgae. Manipulation of competing metabolic pathways by modulating the certain key enzymes such as hydrogenase and nitrogenase may enhance the evolution of H from photoautotrophic cells. Moreover, biological H production at low operating costs is requisite for economic viability. Several photobioreactors have been developed for large-scale biomass and hydrogen production. This review highlights the recent technological progress, enzymes involved and genetic as well as metabolic engineering approaches towards sustainable hydrogen production from microalgae.

Microalgal hydrogen production - A review.

The wastewater discharge from the intensive shrimp aquaculture contains high concentration of nutrients, which can lead to eutrophication. This study aimed to reuse the shrimp wastewater for low cost cyanobacterial cultivation to produce biodegradable plastic poly-β-hydroxybutyrate (PHB). The  sp. PCC 6803 (ΔSphU) lacking phosphate regulator (SphU) could utilize nutrients in shrimp wastewater for promoting biomass yield of 500 mg L after 14 days. The ΔSphU showed the highest phosphate uptake rate of 20.16 mggDwd at the first day of photobioreactor running. In addition, the nutrient removal efficiencies were 96.99% for phosphate, 80.10% for nitrate, 67.90% for nitrite and 98.07% for ammonium. The reduction of nitrate in shrimp wastewater due to nitrogen assimilation could induce PHB accumulation in ΔSphU. The highest PHB content was 32.48% (w/w) DW, with the maximum PHB productivity of 12.73 mg Ld. The produced PHB of ΔSphU had material properties similar to those of the commercial PHB.

Utilization of shrimp wastewater for poly-β-hydroxybutyrate production by  sp. PCC 6803 strain ΔSphU cultivated in photobioreactor.

Enzymatic hydrolysis of the golden oyster mushroom () generated a new bacterial cellulose (BC). The sugar syrup obtained from the hydrolysis of mushroom powder by commercial enzymes gave maximum total soluble solids (TSS) content at 8.83 ± 0.29°Brix, while 8.82 ± 0.06 mg GAE/g substrate of total phenolic content (TPC) was obtained when using initial substrate and enzyme concentrations at 125 g/L and 5.0%, respectively. Glutamic acid, aspartic acid, alanine and valine were determined as the main amino acids found in  hydrolysis at 524.74 ± 0.03, 247.09 ± 0.04, 176.82 ± 0.07 and 174.57 ± 0.01 mg/100 g sample, respectively. Thin-layer chromatography revealed that the obtained sugar syrup was glucose. The hydrolyzed mushroom fermented with  AGR 60 at 30 ± 2 °C for 9 days produced optimal conditions at 4.0°Brix of the initial mushroom syrup and 12.0% (v/v) of the starter culture. Maximum BC thickness was 0.88 ± 0.03 cm with 7.90 ± 0.07 g dry weight, equivalent to 39.50 ± 0.35 g/L and 4.39 ± 0.04 g/L/day for BC production () and BC production rate ( ), respectively. The obtained BC was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, small-angle X-ray scattering and wide-angle X-ray diffraction. These showed the structure and functional properties as a natural source of fiber from the fermentation of a novel substrate.

Conversion of golden oyster mushroom,  to sugar syrup using enzymatic hydrolysis as a substrate for novel bacterial cellulose () fermentation.

This research investigates the effects of landfill leachate effluent concentrations from moving bed biofilm reactor (MBBR) on stress-induced Chlorella vulgaris and Scenedesmus armatus lipid production and post-treatment micropollutant degradation. The effluent concentrations were varied between 25%, 50%, 75%, and 100% (v/v). The landfill leachate influent was treated using two-stage moving bed biofilm reactor under 24 h and 18 h hydraulic retention time (HRT). The results indicated that the effluent concentration was positively correlated with the stress-induced microalgae lipid production in the post-treatment of residual micropollutants. C. vulgaris and S. armatus completely remove residual micropollutants in the effluent. The superoxide dismutase and peroxidase activity were positively correlated with the cellular lipid content. The lipid content of C. vulgaris and S. armatus cultivated in the 18 h HRT effluent were 31-51% and 51-64%, while those in the 24 h HRT effluent were 15-16% and 5-19%. The optimal condition of microalgae cultivation for the post-treatment of residual micropollutants was 50-75% (v/v) effluent concentrations under 18 h HRT, achieving the highest lipid production of 113-116 mg/L for C. vulgaris and 74-75 mg/L for S. armatus. Essentially, the MBBR landfill leachate effluent holds promising potential as a substrate for microalgae lipid production.

Effects of high-strength landfill leachate effluent on stress-induced microalgae lipid production and post-treatment micropollutant degradation.

Shrimp farming wastewater includes high amounts of phosphate and microbiological contaminants, necessitating further treatment before release into receiving water bodies. After 24 h of shrimp wastewater treatment, alginate beads containing the blue-green algal Synechocystis strain lacking the phosphate regulator gene (mutant strain ΔSphU) at 150 mg L reduced phosphate content from 17.5 mg L to 5.0 mg L, representing 71.5% removal efficiency, with phosphate removal rate reaching 6.9 mg gDW h during photobioreactor operation. For short-term treatment, removal rates of nitrate, ammonium and nitrite were 42.7, 48.5 and 92.9%, respectively. Microalgal encapsulated beads also impacted the bacterial community composition dynamics in shrimp wastewater. Next-generation sequencing targeting the V3-V4 region of the 16S rDNA gene showed significant differences in bacterial community composition after 24 h of treatment. Proteobacteria are the most abundant phylum in shrimp wastewater. After 24 h of bioremediation, reductions of harmful bacteria in the Cellvibrionaceae and Pseudomonadaceae families were recorded at 5.85 and 3.18%, respectively. Engineered microalgal immobilization under optimal conditions can be applied as an alternative short-term bioremediation strategy to remove phosphate and other harmful microbial contamination from shrimp farming wastewater.

Highly effective reduction of phosphate and harmful bacterial community in shrimp wastewater using short-term biological treatment with immobilized engineering microalgae.

Editorial: Algal biomass and biofuels.

Polyhydroxybutyrate (PHB) is a biocompatible and biodegradable polymer that has the potential to replace fossil-derived polymers. The enzymes involved in the biosynthesis of PHB are β-ketothiolase (PhaA), acetoacetyl-CoA reductase (PhaB), and PHA synthase (PhaC). PhaC in  is the key enzyme for PHB production. In this study, the recombinant 10G cells harboring  (rPhaC) was constructed. The overexpressed and purified rPhaC with a predicted molecular mass of 69 kDa exhibited , , and  values of 24.5 ± 2 μmol/min/mg, 31.3 ± 2 µM and 412.7 ± 2 1/s, respectively. The catalytically active rPhaC was a homodimer. The three-dimensional structural model for the asymmetric PhaC homodimer was constructed based on  sp. USM2 PhaC (PhaC). The obtained model of PhaC revealed that the overall fold of one monomer was in the closed, catalytically inactive conformation whereas the other monomer was in the catalytically active, open conformation. In the active conformation, the catalytic triad residues (Cys151-Asp310-His339) were involved in the binding of substrate 3HB-CoA and the CAP domain of PhaC involved in the dimerization.

Characterization and Homology Modeling of Catalytically Active Recombinant PhaC Protein from .

The coastal area of Thailand is a tropical marine environment with high microbial diversity, providing favorable conditions for microorganisms capable of degrading bioplastics. The current study aimed to investigate the bacterial community profiling of four samples collected from a coastal area in Thailand and to isolate the potential thermophilic bacteria with the ability to produce bioplastic-degrading enzymes. Our analysis revealed site-specific predominant genera:  in seawater (64.34 ± 0.27%),  in plastic waste (39.69 ± 3.77%),  in soil (54.83 ± 2.40%), and  in moss rock (41.01 ± 1.67%). The thermophilic bacteria, including 6 poly(lactic acid) (PLA)- and 3 poly(butylene succinate) (PBS)-degrading bacteria, were isolated using a two-step technique in an emulsified polymer medium. These nine isolates were classified into five species across four genera: , , , , and . Among these,  LDF1 and  BS2-4 exhibited the highest enzymatic activities for PLA and PBS degradation (0.87 ± 0.11 U/mL and 0.31 ± 0.03 U/mL, respectively). Scanning electron microscopy confirmed the degradation capabilities of these strains in culture medium. Crude enzyme from the LDF1 strain demonstrated versatility in degrading various types of PLA, including PLA film, PLA powder, commercial cup, and commercial cutlery, while the strain BS2-4 enzyme effectively degraded PBS in film, powder, commercial cup, and commercial drinking straw. These findings advance our understanding of coastal microbial ecology and also highlight the potential of indigenous bacteria for bioplastic waste management, contributing to sustainable environmental solutions.

Profiling of the bacterial community and the degradative capability of newly isolated poly(lactic acid) (PLA)- and poly(butylene succinate) (PBS)-degrading bacteria from coastal samples.

Article	Year
Enhancement of poly-3-hydroxybutyrate production in Synechocystis sp. PCC 6803 by overexpression of its native biosynthetic genes. Bioresource technology\| PubMed ID: 27213577	2016
Microalgal hydrogen production - A review. Bioresource technology\| PubMed ID: 28774676	2017
Utilization of shrimp wastewater for poly-β-hydroxybutyrate production by sp. PCC 6803 strain ΔSphU cultivated in photobioreactor. Biotechnology reports (Amsterdam, Netherlands)\| PubMed ID: 31193428	2019
Conversion of golden oyster mushroom, to sugar syrup using enzymatic hydrolysis as a substrate for novel bacterial cellulose () fermentation. 3 Biotech\| PubMed ID: 35935541	2022
Effects of high-strength landfill leachate effluent on stress-induced microalgae lipid production and post-treatment micropollutant degradation. Journal of environmental management\| PubMed ID: 36183533	2022
Highly effective reduction of phosphate and harmful bacterial community in shrimp wastewater using short-term biological treatment with immobilized engineering microalgae. Journal of environmental management\| PubMed ID: 36257228	2023
Editorial: Algal biomass and biofuels. Frontiers in bioengineering and biotechnology\| PubMed ID: 36406216	2022
Characterization and Homology Modeling of Catalytically Active Recombinant PhaC Protein from . Biology\| PubMed ID: 37237563	2023
Profiling of the bacterial community and the degradative capability of newly isolated poly(lactic acid) (PLA)- and poly(butylene succinate) (PBS)-degrading bacteria from coastal samples. 3 Biotech\| PubMed ID: 40978322	2025

Wanthanee Khetkorn

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