Characterization of an alginate lyase, FlAlyA, from Flavobacterium sp. strain UMI-01 and its expression in Escherichia coli

Efficient preparation of alginate oligosaccharides by using alginate lyases and evaluation of the development promoting effects on Brassica napus L. in saline-alkali environment

Enzymatic degradation of alginate for the preparation of alginate oligosaccharides (AOS) is currently receiving significant attention in the field. AOS has been shown to promote crop growth and improve plant resistance to abiotic stresses. In this study, two PL6 family alginate lyases, AlyRmA and AlyRmB, were expressed and characterized. These enzymes demonstrate exceptional activity and stable thermophilicity compared to other known alginate lyases. AlyRmA (8855.34 U/mg) and AlyRmB (7879.44 U/mg) exhibited excellent degradation activity towards sodium alginate even at high temperatures (70 °C). The AlyRmA and AlyRmB were characterized and utilized to efficiently produce AOS. The study investigated the promotional effect of AOS on the growth of Brassica napus L. seedlings in a saline-alkaline environment. The results of this study demonstrate the high activity and thermal stability of AlyRmA and AlyRmB, highlighting their potential in the preparation of AOS. Moreover, the application of AOS prepared by AlyRmB could enhance the resistance of Brassica napus L. to saline-alkali environments, thereby broadening the potential applications of AOS.

In vitro effects of alginate lyase SG4 + produced by Paenibacillus lautus alone and combined with antibiotics on biofilm formation by mucoid Pseudomonas aeruginosa

Alginate is a major extra polymeric substance in the biofilm formed by mucoid Pseudomonas aeruginosa. It is the main proven perpetrator of lung infections in patients suffering from cystic fibrosis. Alginate lyases are very important in the treatment of cystic fibrosis. This study evaluated the role of standalone and in conjugation, effect of alginate lyase of SG4 + isolated from Paenibacillus lautus in enhancing in vitro bactericidal activity of gentamicin and amikacin on mucoid P. aeruginosa. Using Response Surface Methodology (RSM) alginate lyase SG4 + production was optimized in shake flask and there 8.49-fold enhancement in enzyme production. In fermenter, maximum growth (10.15 mg/ml) and alginate lyase (1.46 International Units) production, 1.71-fold was increased using Central Composite Design (CCD). Further, fermentation time was reduced from 48 to 20 h. To the best of our knowledge this is the first report in which CCD was used for fermenter studies to optimize alginate lyase production. The Km and Vmax of purified enzyme were found to be 2.7 mg/ml and 0.84 mol/ml-min, respectively. The half-life (t 1/2) of purified alginate lyase SG4 + at 37 °C was 180 min. Alginate lyase SG4 + in combination with gentamicin and amikacin eradiated 48.4- 52.3% and 58- 64.6%, alginate biofilm formed by P. aeruginosa strains, respectively. The study proves that alginate lyase SG4 + has excellent exopolysaccharide disintegrating ability and may be useful in development of potent therapeutic agent to treat P. aeruginosa biofilms.

Expression and Characterization of an Efficient Alginate Lyase from Psychromonas sp. SP041 through Metagenomics Analysis of Rotten Kelp

Alginate is derived from brown algae, which can be cultivated in large quantities. It can be broken down by alginate lyase into alginate oligosaccharides (AOSs), which exhibit a higher added value and better bioactivity than alginate. In this study, metagenomic technology was used to screen for genes that code for high-efficiency alginate lyases. The candidate alginate lyase gene alg169 was detected from Psychromonas sp. SP041, the most abundant species among alginate lyase bacteria on selected rotten kelps. The alginate lyase Alg169 was heterologously expressed in Escherichia coli BL21 (DE3), Ni-IDA-purified, and characterized. The optimum temperature and pH of Alg169 were 25 °C and 7.0, respectively. Metal ions including Mn2+, Co2+, Ca2+, Mg2+, Ni2+, and Ba2+ led to significantly increased enzyme activity. Alg169 exhibited a pronounced dependence on Na+, and upon treatment with Mn2+, its activity surged by 687.57%, resulting in the highest observed enzyme activity of 117,081 U/mg. Bioinformatic analysis predicted that Alg169 would be a double-domain lyase with a molecular weight of 65.58 kDa. It is a bifunctional enzyme with substrate specificity to polyguluronic acid (polyG) and polymannuronic acid (polyM). These results suggest that Alg169 is a promising candidate for the efficient manufacturing of AOSs from brown seaweed.

Preliminary identification and semi-quantitative characterization of a multi-faceted high-stability alginate lyase from marine microbe Seonamhaeicola algicola with anti-biofilm effect on Pseudomonas aeruginosa

Alginate lyases with unique characteristics for degrading alginate into size-defined oligosaccharide fractions, were considered as the potential agents for disrupting Pseudomonas aeruginosa biofilms. In our study, a novel endolytic PL-7 alginate lyase, named AlyG2, was cloned and expressed through Escherichia coli. This enzyme exhibited excellent properties: it maintained more than 85% activity at low temperatures of 4 °C and high temperatures of 70 °C. After 1 h of incubation at 4 °C, it still retained over 95% activity, demonstrating the ability to withstand low temperature. The acid-base and salt tolerance properties shown it preserves more than 50% activity in the pH range of 5.0 to 11.0 and in a high salt environment at 3000 mM NacCl, indicating its high stability in several aspects. More importantly, AlyG2 in our research was revealed to be effective at removing mature biofilms and inhibiting biofilm formation produced by Pseudomonas aeruginosa, and the inhibition and disruption rates were 47.25 ± 4.52% and 26.5 ± 6.72%, respectively. Additionally, the enzyme AlyG2 promoted biofilm disruption in combination with antibiotics, particularly manifesting the synergistic effect with erythromycin (FIC=0.5). In all, these results offered that AlyG2 with unique characteristics may be an effective technique for the clearance or disruption of biofilm produced by P. aeruginosa.

Advances in alginate lyases and the potential application of enzymatic prepared alginate oligosaccharides: A mini review

Alginate is mainly a linear polysaccharide composed of randomly arranged β-D-mannuronic acid and α-L-guluronic acid linked by α, β-(1,4)-glycosidic bonds. Alginate lyases degrade alginate mainly adopting a β-elimination mechanism, breaking the glycosidic bonds between the monomers and forming a double bond between the C4 and C5 sugar rings to produce alginate oligosaccharides consisting of 2-25 monomers, which have various physiological functions. Thus, it can be used for the continuous industrial production of alginate oligosaccharides with a specific degree of polymerization, in accordance with the requirements of green exploitation of marine resources. With the development of structural analysis, the quantity of characterized alginate lyase structures is progressively growing, leading to a concomitant improvement in understanding the catalytic mechanism. Additionally, the use of molecular modification methods including rational design, truncated expression of non-catalytic domains, and recombination of conserved domains can improve the catalytic properties of the original enzyme, enabling researchers to screen out the enzyme with the expected excellent performance with high success rate and less workload. This review presents the latest findings on the catalytic mechanism of alginate lyases and outlines the methods for molecular modifications. Moreover, it explores the connection between the degree of polymerization and the physiological functions of alginate oligosaccharides, providing a reference for enzymatic preparation development and utilization.

Identification and characterization of a critical loop for the high activity of alginate lyase VaAly2 from the PL7_5 subfamily

As the major component in the cell wall of brown algae, alginates are degradable by alginate lyases via β-elimination. Alginate lyases can be categorized into various polysaccharide lyase (PL) families, and PL7 family alginate lyases are the largest group and can be divided into six subfamilies. However, the major difference among different PL7 subfamilies is not fully understood. In this work, a marine alginate lyase, VaAly2, from Vibrio alginolyticus ATCC 17749 belonging to the PL7_5 subfamily was identified and characterized. It displayed comparatively high alginolytic activities toward different alginate substrates and functions as a bifunctional lyase. Molecular docking and biochemical analysis suggested that VaAly2 not only contains a key catalyzing motif (HQY) conserved in the PL7 family but also exhibits some specific characters limited in the PL7_5 subfamily members, such as the key residues and a long loop1 structure around the active center. Our work provides insight into a loop structure around the center site which plays an important role in the activity and substrate binding of alginate lyases belonging to the PL7_5 subfamily.

Preparation, Structural Characterization, and Enzymatic Properties of Alginate Lyase Immobilized on Magnetic Chitosan Microspheres

Alginate lyase is an enzyme that catalyses the hydrolysis of alginate into alginate oligoalginates. To enhance enzyme stability and recovery, a facile strategy for alginate lyase immobilization was developed. Novel magnetic chitosan microspheres were synthesized and used as carriers to immobilize alginate lyase. The immobilization of alginate lyase on magnetic chitosan microspheres was successful, as proven by Fourier transform infrared spectroscopy and X-ray diffraction spectra. Enzyme immobilization exhibited the best performance at an MCM dosage of 1.5 g/L, adsorption time of 2.0 h, glutaraldehyde concentration of 0.2%, and immobilization time of 2.0 h. The optimal pH of the free alginate lyase was 7.5, and this pH value was shifted to 8.0 after immobilization. No difference was observed at the optimal temperature (45 °C) for the immobilized and free enzymes. The immobilized alginate lyase displayed better thermal stability than the free alginate lyase. The Km values of the free and immobilized enzymes were 0.05 mol/L and 0.09 mol/L, respectively. The immobilized alginate lyase retained 72% of its original activity after 10 batch reactions. This strategy was found to be a promising method for immobilizing alginate lyase.

A Novel Cold-Adapted and High-Alkaline Alginate Lyase with Potential for Alginate Oligosaccharides Preparation

Alginate oligosaccharides (AOs) prepared through enzymatic reaction by diverse alginate lyases under relatively controllable and moderate conditions possess versatile biological activities. But widely used commercial alginate lyases are still rather rare due to their poor properties (e.g., lower activity, worse thermostability, ion tolerance, etc.). In this work, the alginate lyase Alyw208, derived from Vibrio sp. W2, was expressed in Yarrowia lipolytica of food grade and characterized in order to obtain an enzyme with excellent properties adapted to industrial requirements. Alyw208 classified into the polysaccharide lyase (PL) 7 family showed maximum activity at 35 °C and pH 10.0, indicating its cold-adapted and high-alkaline properties. Furthermore, Alyw208 preserved over 70% of the relative activity within the range of 10-55 °C, with a broader temperature range for the activity compared to other alginate-degrading enzymes with cold adaptation. Recombinant Alyw208 was significantly activated with 1.5 M NaCl to around 2.1 times relative activity. In addition, the endolytic Alyw208 was polyG-preferred, but identified as a bifunctional alginate lyase that could degrade both polyM and polyG effectively, releasing AOs with degrees of polymerization (DPs) of 2-6 and alginate monomers as the final products (that is, DPs 1-6). Alyw208 has been suggested with favorable properties to be a potent candidate for biotechnological and industrial applications.

Efficient Degradation of Alginate and Preparation of Alginate Oligosaccharides by a Novel Biofunctional Alginate Lyase with High Activity and Excellent Thermophilic Features

The enzymatic degradation of seaweed polysaccharides is gaining interest for its potential in the production of functional oligosaccharides and fermentable sugars. Herein, a novel alginate lyase, AlyRm3, was cloned from a marine strain, Rhodothermus marinus DSM 4252. The AlyRm3 showed optimal activity (37,315.08 U/mg) at 70 °C and pH 8.0, with the sodium alginate used as a substrate. Noticeably, AlyRm3 was stable at 65 °C and also exhibited 30% of maximal activity at 90 °C. These results indicated that AlyRm3 is a thermophilic alginate lyase that efficiently degrades alginate at high industrial temperatures (>60 °C). The FPLC and ESI−MS analyses suggested that AlyRm3 primarily released disaccharides and trisaccharides from the alginate, polyM, and polyG in an endolytic manner. In the saccharification process of sodium alginate (0.5%, w/v), the AlyRm3 yielded numerous reducing sugars (1.73 g/L) after 2 h of reaction. These results indicated that AlyRm3 has a high enzymatic capacity for saccharifying the alginate, and could be used to saccharify the alginate biomass before the main fermentation process for biofuels. These properties make AlyRm3 a valuable candidate for both fundamental research and industrial applications.

Cell aggregation is associated with enzyme secretion strategies in marine polysaccharide-degrading bacteria

Polysaccharide breakdown by bacteria requires the activity of enzymes that degrade polymers either intra- or extra-cellularly. The latter mechanism generates a localized pool of breakdown products that are accessible to the enzyme producers themselves as well as to other organisms. Marine bacterial taxa often show marked differences in the production and secretion of degradative enzymes that break down polysaccharides. These differences can have profound effects on the pool of diffusible breakdown products and hence on the ecological dynamics. However, the consequences of differences in enzymatic secretions on cellular growth dynamics and interactions are unclear. Here we study growth dynamics of single cells within populations of marine Vibrionaceae strains that grow on the abundant marine polymer alginate, using microfluidics coupled to quantitative single-cell analysis and mathematical modelling. We find that strains that have low extracellular secretions of alginate lyases aggregate more strongly than strains that secrete high levels of enzymes. One plausible reason for this observation is that low secretors require a higher cellular density to achieve maximal growth rates in comparison with high secretors. Our findings indicate that increased aggregation increases intercellular synergy amongst cells of low-secreting strains. By mathematically modelling the impact of the level of degradative enzyme secretion on the rate of diffusive oligomer loss, we find that enzymatic secretion capability modulates the propensity of cells within clonal populations to cooperate or compete with each other. Our experiments and models demonstrate that enzymatic secretion capabilities can be linked with the propensity of cell aggregation in marine bacteria that extracellularly catabolize polysaccharides.

Insights into the Influence of Signal Peptide on the Enzymatic Properties of Alginate Lyase AlyI1 with Removal Effect on Pseudomonas aeruginosa Biofilm

Most reports on signal peptides focus on their ability to affect the normal folding of proteins, thereby affecting their secreted expression, while few studies on its effects on enzymatic properties were published. Therefore, biochemical characterization and comparison of alginate lyase rALYI1/rALYI1-1 (rALYI1: without signal peptides; rALYI1-1:with signal peptides) were conducted in our study, and the results showed that the signal peptide affected the biochemical properties, especially in temperature and pH. rALYI1 (32.15 kDa) belonging to polysaccharide lyase family 7 was cloned from sea-cucumber-gut bacterium Tamlana sp. I1. The optimum temperature of both rALYI1 and rALYI1-1 was 40 °C, but the former had a wider optimum temperature range and better thermal stability. The optimum pH of rALYI1 and rALYI1-1 were 7.6 and 8.6, respectively. The former was more stable and acid resistant. Noticeably, rALYI1 was a salt-activated enzyme and displayed remarkable salt tolerance. Alginate, an essential polysaccharide in algae and Pseudomonas aeruginosa biofilms, is composed of α-L-guluronate and β-D-mannuronate. It is also found in our study that rALYI1 is also effective in removing mature biofilms compared with controls. In conclusion, the signal peptide affects several biochemical properties of the enzyme, and alginate lyase rALYI1 may be an effective method for inhibiting biofilm formation of Pseudomonas aeruginosa.

Improving the thermostability of alginate lyase FlAlyA with high expression by computer-aided rational design for industrial preparation of alginate oligosaccharides

FlAlyA, a PL7 alginate lyase with industrial potential, is widely applied in the preparation the alginate oligosaccharide because of its high activity of degradation the alginate. However, heat inactivation still limits the industrial application of FlAlyA. To further enhance its thermostability, a group of mutants were designed, according to evaluating the B-factor value and free energy change via computer-aided calculation. 25 single-point mutants and one double-points mutant were carried out by site-directed mutagenesis. The optimal two single-point mutants H176D and H71K showed 1.20 and 0.3°C increases in the values of T m, while 7.58 and 1.73 min increases in the values of half-life (t 1/2) at 50°C, respectively, compared with that of the wild-type enzyme. Interestingly, H71K exhibits the comprehensive improvement than WT, including expression level, thermal stability and specific activity. In addition, the mechanism of these two mutants is speculated by multiple sequence alignment, structural basis and molecular dynamics simulation, which is likely to be involved in the formation of new hydrogen bonds and decrease the SASA of the mutants. These results indicate that B-factor is an efficient approach to improves the thermostability of alginate lyase composed of β-sheet unit. Furthermore, the highest yield of the mutant reached about 650 mg/L, which was nearly 36 times that of previous studies. The high expression, excellent activity and good thermal stability make FlAlyA a potential candidate for the industrial production of alginate oligosaccharides.

An oxidative metabolic pathway of 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEHU) from alginate in an alginate-assimilating bacterium

Alginate-assimilating bacteria degrade alginate into an unsaturated monosaccharide, which is converted into 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEHU). DEHU is reduced to 2-keto-3-deoxy-D-gluconate by a DEHU-specific reductase using NAD(P)H. This is followed by pyruvate production via the Entner-Doudoroff pathway. Previously, we identified FlRed as a DEHU reductase in an alginate-assimilating bacterium, Flavobacterium sp. strain UMI-01. Here, we showed that FlRed can also catalyze the oxidation of DEHU with NAD⁺, producing 2-keto-3-deoxy-D-glucarate (KDGR). FlRed showed a predilection for NADH and NAD⁺ over NADPH and NADP⁺, respectively, and the K_m value for NADH was approximately 2.6-fold less than that for NAD⁺. Furthermore, we identified two key enzymes, FlDet and FlDeg, for KDGR catabolism. FlDet was identified as an enzyme of the ribonuclease activity regulator A family, which converts KDGR to α-ketoglutaric semialdehyde (α-KGSA). FlDeg, a type II α-KGSA dehydrogenase, generated α-ketoglutaric acid by oxidizing the aldehyde group of α-KGSA using NAD(P)⁺. Consequently, unlike the conventional DEHU reduction pathway, DEHU can be directly converted to α-ketoglutaric acid without consuming NAD(P)H. Alginate upregulated the expression of not only FlRed and two enzymes of the DEHU-reduction pathway, but also FlDet and FlDeg. These results revealed dual pathways of DEHU metabolism involving reduction or oxidation by FlRed.

Genome-Wide Analysis of PL7 Alginate Lyases in the Genus Zobellia

We carried out a detailed investigation of PL7 alginate lyases across the Zobellia genus. The main findings were obtained using the methods of comparative genomics and spatial structure modeling, as well as a phylogenomic approach. Initially, in order to elucidate the alginolytic potential of Zobellia, we calculated the content of polysaccharide lyase (PL) genes in each genome. The genus-specific PLs were PL1, PL6, PL7 (the most abundant), PL14, PL17, and PL40. We revealed that PL7 belongs to subfamilies 3, 5, and 6. They may be involved in local and horizontal gene transfer and gene duplication processes. Most likely, an individual evolution of PL7 genes promotes the genetic variability of the Alginate Utilization System across Zobellia. Apparently, the PL7 alginate lyases may acquire a sub-functionalization due to diversification between in-paralogs.

Characterization of a New Biofunctional, Exolytic Alginate Lyase from Tamlana sp. s12 with High Catalytic Activity and Cold-Adapted Features

Alginate, a major acidic polysaccharide in brown algae, has attracted great attention as a promising carbon source for biorefinery systems. Alginate lyases, especially exo-type alginate lyase, play a critical role in the biorefinery process. Although a large number of alginate lyases have been characterized, few can efficiently degrade alginate comprised of mannuronate (M) and guluronate (G) at low temperatures by means of an exolytic mode. In this study, the gene of a new exo-alginate lyase-Alys1-with high activity (1350 U/mg) was cloned from a marine strain, Tamlana sp. s12. When sodium alginate was used as a substrate, the recombinant enzyme showed optimal activity at 35 °C and pH 7.0-8.0. Noticeably, recombinant Alys1 was unstable at temperatures above 30 °C and had a low melting temperature of 56.0 °C. SDS and EDTA significantly inhibit its activity. These data indicate that Alys1 is a cold-adapted enzyme. Moreover, the enzyme can depolymerize alginates polyM and polyG, and produce a monosaccharide as the minimal alginate oligosaccharide. Primary substrate preference tests and identification of the final oligosaccharide products demonstrated that Alys1 is a bifunctional alginate lyase and prefers M to G. These properties make Alys1 a valuable candidate in both basic research and industrial applications.

Functional identification of the 4-deoxy-L-erythro-5-hexoseulose uronate reductase from a brown alga, Saccharina japonica

We previously reported the alginate lyase, SjAly, from a brown alga, Saccharina japonica, providing the first experimental evidence for a functional alginate-degradation enzyme in brown algae. 4-deoxy-L-erythro-5-hexoseulose uronate (DEHU), derived from an unsaturated monosaccharide, was identified as the minimum degradation product produced by SjAly-mediated lysis of alginate. DEHU was hitherto reported to be reduced to 2-keto-3-deoxy-gluconate (KDG) by a DEHU-specific reductase with NAD(P)H in alginate-assimilating organisms and its metabolism in alginate-producing organisms is unknown. Here, we report the functional identification of a DEHU reductase, SjRed, in S. japonica. Among the 14 tested compounds, only DEHU was used as a substrate and was converted to KDG in the presence of NADPH. Optimum temperature, pH, and KCl concentration required for SjRed activity were determined to be 25 °C, 7.2, and 100 mM, respectively. SjRed consists of 341 amino acid residues and is proposed to be a member of the aldo-keto reductase superfamily. Sequencing of SjRed revealed that it is composed of at least three exons. These results indicate the existence of an enzyme that reduces DEHU to KDG in S. japonica. This is the first report on the functional identification of a DEHU-reductase in alginate-producing organisms.

Cellulophaga algicola alginate lyase inhibits biofilm formation of a clinical Pseudomonas aeruginosa strain MCC 2081

Alginate lyases are potential agents for disrupting alginate-rich Pseudomonas biofilms in the infected lungs of cystic fibrosis patients but there is as yet no clinically approved alginate lyase that can be used as a therapeutic. We report here the endolytic alginate lyase activity of a recombinant Cellulophaga algicola alginate lyase domain (CaAly) encoded by a gene that also codes for an N-terminal carbohydrate-binding module, CBM6, and a central F-type lectin domain (CaFLD). CaAly degraded both polyM and polyG alginates with optimal temperature and pH of 37°C and pH 7, respectively, with greater preference for polyG. Recombinant CaFLD bound to fucosylated glycans with a preference for H-type 2 glycan motif, and did not have any apparent effect on the enzyme activity of the co-associated alginate lyase domain in the recombinant protein construct, CaFLD_Aly. We assessed the potential of CaAly and other alginate lyases previously reported in published literature to inhibit biofilm formation by a clinical strain, Pseudomonas aeruginosa MCC 2081. Of all the alginate lyases tested, CaAly displayed most inhibition of in vitro biofilm formation on plastic surfaces. We also assessed its inhibitory ability against P. aeruginosa 2081 biofilms formed over a monolayer of A549 lung epithelial cells. Our study indicated that CaAly is efficacious in inhibition of biofilm formation even on A549 lung epithelial cell line monolayers.

Characteristics and applications of alginate lyases: A review

Brown algae, as the main source of alginate, are a type of marine biomass with a very high output. Alginate, a polysaccharide composed of β-D-mannuronic acid (M) and α-L-guluronic acid (G), has great potential for applications in the food, cosmetic and pharmaceutical industries. Alginate lyases (Alys) can degrade alginate polymers into oligosaccharides or monosaccharides, resulting in a broad application field. Alys can be used for both the production of alginate oligosaccharides and the biorefinery of brown algae. In view of their important functions, an increasing number of Alys have been isolated and characterized. For better application, a comprehensive understanding of Alys is essential. Therefore, in this paper, we summarized recently discovered Alys, discussed their characteristics, and introduced their structural properties, degradation patterns and biological roles in alginate-degrading organisms. In addition, applications of Alys have been illustrated with examples. This paper provides a relatively comprehensive description of Alys, which is significant for Alys exploration and application.

Marine-polysaccharide degrading enzymes: Status and prospects

Marine-polysaccharide degrading enzymes have recently been studied extensively. They are particularly interesting as they catalyze the cleavage of glycosidic bonds in polysaccharide macromolecules and produce oligosaccharides with low degrees of polymerization. Numerous findings have demonstrated that marine polysaccharides and their biotransformed products possess beneficial properties including antitumor, antiviral, anticoagulant, and anti-inflammatory activities, and they have great value in healthcare, cosmetics, the food industry, and agriculture. Exploitation of enzymes that can degrade marine polysaccharides is in the ascendant, and is important for high-value use of marine biomass resources. In this review, we describe research and prospects regarding the classification, biochemical properties, and catalytic mechanisms of the main types of marine-polysaccharide degrading enzymes, focusing on chitinase, chitosanase, alginate lyase, agarase, and carrageenase, and their product oligosaccharides. The state-of-the-art discussion of marine-polysaccharide degrading enzymes and their properties offers information that might enable more efficient production of marine oligosaccharides. We also highlight current problems in the field of marine-polysaccharide degrading enzymes and trends in their development. Understanding the properties, catalytic mechanisms, and modification of known enzymes will aid the identification of novel enzymes to degrade marine polysaccharides and facilitation of their use in various biotechnological processes.

Characterization of a New Bifunctional and Cold-Adapted Polysaccharide Lyase (PL) Family 7 Alginate Lyase from Flavobacterium sp

Alginate oligosaccharides produced by enzymatic degradation show versatile physiological functions and biological activities. In this study, a new alginate lyase encoding gene alyS02 from Flavobacterium sp. S02 was recombinantly expressed at a high level in Yarrowia lipolytica, with the highest extracellular activity in the supernatant reaching 36.8 ± 2.1 U/mL. AlyS02 was classified in the polysaccharide lyase (PL) family 7. The optimal reaction temperature and pH of this enzyme were 30 °C and 7.6, respectively, indicating that AlyS02 is a cold-adapted enzyme. Interestingly, AlyS02 contained more than 90% enzyme activity at 25 °C, higher than other cold-adapted enzymes. Moreover, AlyS02 is a bifunctional alginate lyase that degrades both polyG and polyM, producing di- and trisaccharides from alginate. These findings suggest that AlyS02 would be a potent tool for the industrial applications.

Disruption of the extracellular polymeric network of Pseudomonas aeruginosa biofilms by alginate lyase enhances pathogen eradication by antibiotics

BACKGROUND

Pseudomonas aeruginosa forms antibiotic-resistant biofilms that are responsible for the treatment failure or relapses of the bacterial infections in the lungs of patients with cystic fibrosis (CF). The alginate lyases that target extracellular polysaccharide alginate of P. aeruginosa biofilms are promising therapeutic candidates for treatment of P. aeruginosa biofilm infections.

METHODS

Immunofluorescent staining and thin layer chromatography were used to demonstrate the alginolytic activity of the alginate lyase enzyme (AlyP1400) purified from a marine Pseudoalteromonas bacterium. Anti-biofilm activities of AlyP1400 were tested alone or in combination with antibiotics on the biofilms of a mucoid Pseudomonas aeruginosa clinical isolate CF27 that were cultivated in 96-well plates and a flow cell.

RESULTS

We showed that AlyP1400 facilitated antibiotic activities to eliminate CF27 biofilms. The combination of AlyP1400 with antibiotics reduced the biofilm biomass and boosted bactericidal activity of antibiotics. Importantly, we demonstrated that the enzymatic activity of AlyP1400 was required for its biofilm disruption activity and its synergy with antibiotics to eradicate biofilm cells.

CONCLUSION

This work shed new light on the potential mechanisms of the therapeutic activity for the combinational use of alginate lyase and antibiotics to treat P. aeruginosa infections in CF lungs or other P. aeruginosa biofilm-related infections.

Production of a novel dimeric 4-deoxy-L-erythro-5-hexoseulose uronic acid by a PL-17 exolytic alginate lyase from Hydrogenophaga sp. UMI-18

Hydrogenopahaga sp. strain UMI-18 is an alginolytic bacterium that can produce poly(3-hydroxybutylate) (PHB) using alginate as its sole carbon source. Genome analysis indicated that this strain harbors both PHB-synthesizing and alginate-assimilating gene clusters. In the present study, we cloned HyAly-I gene that encodes a PL-17 exolytic alginate lyase and investigated its enzymatic properties using recombinant HyAly-I (recHyAly-I) that was produced by Escherichia coli. The recHyAly-I preferably depolymerized poly(β-D-mannuronate) block of alginate in an exolytic manner at an optimal temperature and a pH at 40 °C and pH 6.0, respectively. It released 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH) from the non-reducing terminus of polymer and oligomer substrates. Interestingly, recHyAly-I was found to produce a novel unsaturated disaccharide, i.e., dimeric DEH (diDEH), along with monomeric DEH. Production of diDEH was prominent in the degradation of trisaccharides.

Purification and Characterization of a Novel Endolytic Alginate Lyase from Microbulbifer sp. SH-1 and Its Agricultural Application

Alginate, an important acidic polysaccharide in marine multicellular algae, has attracted attention as a promising biomass resource for the production of medical and agricultural chemicals. Alginate lyase is critical for saccharification and utilization of alginate. Discovering appropriate and efficient enzymes for depolymerizing alginate into fermentable fractions plays a vital role in alginate commercial exploitation. Herein, a unique alginate lyase, AlgSH7, belonging to polysaccharide lyase 7 family is purified and characterized from an alginate-utilizing bacterium Microbulbifer sp. SH-1. The purified AlgSH7 shows a specific activity of 12,908.26 U/mg, and its molecular weight is approximately 66.4 kDa. The optimal temperature and pH of AlgSH7 are 40 °C and pH 9.0, respectively. The enzyme exhibits stability at temperatures below 30 °C and within an extensive pH range of 5.0-9.0. Metal ions including Na⁺, K⁺, Al³⁺, and Fe³⁺ considerably enhance the activity of the enzyme. AlgSH7 displays a preference for poly-mannuronic acid (polyM) and a very low activity towards poly-guluronic acid (polyG). TLC and ESI-MS analysis indicated that the enzymatic hydrolysates mainly include disaccharides, trisaccharides, and tetrasaccharides. Noteworthy, the alginate oligosaccharides (AOS) prepared by AlgSH7 have an eliciting activity against chilling stress in Chinese flowering cabbage (Brassica parachinensis L.). These results suggest that AlgSH7 has a great potential to design an effective process for the production of alginate oligomers for agricultural applications.

Characterization of an Alkaline Alginate Lyase with pH-Stable and Thermo-Tolerance Property

Alginate oligosaccharides (AOS) show versatile bioactivities. Although various alginate lyases have been characterized, enzymes with special characteristics are still rare. In this study, a polysaccharide lyase family 7 (PL7) alginate lyase-encoding gene, aly08, was cloned from the marine bacterium Vibrio sp. SY01 and expressed in Escherichia coli. The purified alginate lyase Aly08, with a molecular weight of 35 kDa, showed a specific activity of 841 U/mg at its optimal pH (pH 8.35) and temperature (45 °C). Aly08 showed good pH-stability, as it remained more than 80% of its initial activity in a wide pH range (4.0–10.0). Aly08 was also a thermo-tolerant enzyme that recovered 70.8% of its initial activity following heat shock treatment for 5 min. This study also demonstrated that Aly08 is a polyG-preferred enzyme. Furthermore, Aly08 degraded alginates into disaccharides and trisaccharides in an endo-manner. Its thermo-tolerance and pH-stable properties make Aly08 a good candidate for further applications.

Effects of module truncation on biochemical characteristics and products distribution of a new alginate lyase with two catalytic modules

In this work, we investigated the functions of structural modules within alginate lyase by truncating an endo-type alginate lyase into two successive catalytic modules. The effects of module deletion on biochemical characteristics and product distributions were further investigated. The N-terminal module (Aly7B-CDI) exhibited no activity toward alginate, polyM or polyG, but the C-terminal module (Aly7B-CDII) retained its activity. The full-length enzyme (Aly7B) and its truncated counterpart (Aly7B-CDII) had similar substrate specificities, but Aly7B-CDII had lower activity. Moreover, the activity of Aly7B was much higher than Aly7B-CDII at 30°C. Aly7B-CDII, however, possessed higher optimal pH and better pH stability than the full-length enzyme. The final degradation products for Aly7B were unsaturated di-, tri- and tetra-oligosaccharides, and those for Aly7B-CDII were unsaturated mono-, di-, tri-, tetra- and penta-oligosaccharides. Therefore, the potential impact of the noncatalytic module Aly7B-CDI on the catalytic module Aly7B-CDII was further elucidated by characterizing Aly7B and its truncations. These data contribute to the functional understanding of these differing modules.

Functional identification of alginate lyase from the brown alga Saccharina japonica

Despite the progress in massive gene analysis of brown algal species, no alginate-degrading enzyme from brown alga has been identified, impeding the understanding of alginate metabolism in brown alga. In the current study, we identified and characterized alginate lyase from Saccharina japonica using a protein-based approach. First, cDNA library was prepared from the S. japonica sporophyte. Expression screening was then performed; the encoding gene was identified and cloned; and the recombinant enzyme was purified and characterized. Alginate lyase production in algal tissues was evaluated by western blotting. The identified alginate lyase, SjAly (359 amino acids, with a predicted N-terminal secretion signal of 27 residues), is encoded by an open reading frame comprising seven exons. Recombinant SjAly exhibited endolytic alginate lyase activity, specifically toward stretches of consecutive β-D-mannuronic acid units. The optimum temperature, pH, and NaCl concentration were 30 °C, pH 8.0, and 100 mM, respectively. SjAly exhibited pronounced activity below 20 °C, the S. japonica growth temperature. SjAly was highly expressed in the blade but not the stipe and rhizoid. The data indicate that S. japonica possesses at least one active alginate lyase. This is the first report of a functional alginate lyase from brown alga, the major natural alginate producer.

Cloning, expression and characterization of an endo-acting bifunctional alginate lyase of marine bacterium Wenyingzhuangia fucanilytica

Alginate is the major constituent of brown algae and a commercially important polysaccharide with wide applications. Alginate lyases are desired tools for degrading alginate. Based on the genome mining of marine bacterium Wenyingzhuangia funcanilytica, an alginate lyase Aly7B_Wf was discovered, cloned and expressed in Escherichia coli. Aly7B_Wf belonged to subfamily 6 of PL7 family. Its biochemical properties, kinetic constants, substrate specificity and degradation pattern were clarified. The enzyme is an endo-acting bifunctional alginate lyase, and preferably cleaved polymannuronate (polyM). The K_m (0.0237 ± 0.0004 μM, 0.0105 ± 0.0002 mg/mL) and k_cat/K_m (1180.65 ± 19.81 μM^-1 s^-1, 2654.34 ± 44.54 mg^-1 ml s^-1) indicated relatively high substrate-binding affinity and catalysis efficiency of Aly7B_Wf. By using mass spectrometry, final products of alginate degraded by Aly7B_Wf were identified as alginate hexasaccharide to disaccharide, and final products of polyguluronate (polyG) and polyM were confirmed as tetrasaccharide to disaccharide. The most predominant oligosaccharide in the final products of polyG and polyM was trisaccharide and disaccharide respectively. The broad substrate specificity, endo-acting degradation pattern and high catalysis efficiency suggested that Aly7B_Wf could be utilizied as a potential tool for tailoring the size of alginate and preparing alginate oligosaccharides.

Characterization of a Novel PolyM-Preferred Alginate Lyase from Marine Vibrio splendidus OU02

Alginate lyases are enzymes that degrade alginate into oligosaccharides which possess a variety of biological activities. Discovering and characterizing novel alginate lyases has great significance for industrial and medical applications. In this study, we reported a novel alginate lyase, AlyA-OU02, derived from the marine Vibrio splendidus OU02. The BLASTP searches showed that AlyA-OU02 belonged to polysaccharide lyase family 7 (PL7) and contained two consecutive PL7 domains, which was rare among the alginate lyases in PL7 family. Both the two domains, AlyA^a and AlyA^b, had lyase activities, while AlyA^a exhibited polyM preference, and AlyA^b was polyG-preferred. In addition, the enzyme activity of AlyA^a was much higher than AlyA^b at 25 °C. The full-length enzyme of AlyA-OU02 showed polyM preference, which was the same as AlyA^a. AlyA^a degraded alginate into di-, tri-, and tetra-alginate oligosaccharides, while AlyA^b degraded alginate into tri-, tetra-, and penta-alginate oligosaccharides. The degraded products of AlyA-OU02 were similar to AlyA^a. Our work provided a potential candidate in the application of alginate oligosaccharide production and the characterization of the two domains might provide insights into the use of alginate of this organism.

High-Level Expression of a Thermally Stable Alginate Lyase Using Pichia pastoris, Characterization and Application in Producing Brown Alginate Oligosaccharide

An alginate lyase encoding gene sagl from Flavobacterium sp. H63 was codon optimized and recombinantly expressed at high level in P.pastoris through high cell-density fermentation. The highest yield of recombinant enzyme of sagl (rSAGL) in yeast culture supernatant reached 226.4 μg/mL (915.5 U/mL). This was the highest yield record of recombinant expression of alginate lyase so far. The rSAGL was confirmed as a partially glycosylated protein through EndoH digestion. The optimal reaction temperature and pH of this enzyme were 45 °C and 7.5; 80 mM K⁺ ions could improve the catalytic activity of the enzyme by 244% at most. rSAGL was a thermal stable enzyme with T50¹⁵ of 57⁻58 °C and T50³⁰ of 53⁻54 °C. Its thermal stability was better than any known alginate lyase. In 100 mM phosphate buffer of pH 6.0, rSAGL could retain 98.8% of the initial activity after incubation at 50 °C for 2 h. Furthermore, it could retain 61.6% of the initial activity after 48 h. The specific activity of the purified rSAGL produced by P. pastoris attained 4044 U/mg protein, which was the second highest record of alginate lyase so far. When the crude enzyme of the rSAGL was directly used in transformation of sodium alginate with 40 g/L, 97.2% of the substrate was transformed to di, tri, tetra brown alginate oligosaccharide after 32 h of incubation at 50 °C, and the final concentration of reducing sugar in mixture reached 9.51 g/L. This is the first report of high-level expression of thermally stable alginate lyase using P. pastoris system.

Characterization of PL-7 Family Alginate Lyases From Marine Organisms and Their Applications

Alginate, an anionic heteropolysaccharide extracted from natural brown algae, has useful properties for the food, chemical, medical, and agricultural industries. Degradation of alginate by alginate lyase is a key process to produce unsaturated oligoalginate and unsaturated monosaccharide 4-deoxy-l-erythro-5-hexoseulose uronic acid. Alginate lyases belonging to the polysaccharide lyase family 7 have been found in, and isolated from, organisms thriving in various environments. Furthermore, research on their function and structure has also progressed well. Here, the preparation of native and recombinant PL-7 alginate lyases and the methods for evaluation of enzymatic activity are summarized. Examples of PL-7 alginate lyase applications are also described.

Purification and Characterization of a Novel Alginate Lyase from the Marine Bacterium Bacillus sp. Alg07

Alginate oligosaccharides with different bioactivities can be prepared through the specific degradation of alginate by alginate lyases. Therefore, alginate lyases that can be used to degrade alginate under mild conditions have recently attracted public attention. Although various types of alginate lyases have been discovered and characterized, few can be used in industrial production. In this study, AlgA, a novel alginate lyase with high specific activity, was purified from the marine bacterium Bacillus sp. Alg07. AlgA had a molecular weight of approximately 60 kDa, an optimal temperature of 40 °C, and an optimal pH of 7.5. The activity of AlgA was dependent on sodium chloride and could be considerably enhanced by Mg²⁺ or Ca²⁺. Under optimal conditions, the activity of AlgA reached up to 8306.7 U/mg, which is the highest activity recorded for alginate lyases. Moreover, the enzyme was stable over a broad pH range (5.0–10.0), and its activity negligibly changed after 24 h of incubation at 40 °C. AlgA exhibited high activity and affinity toward poly-β-d-mannuronate (polyM). These characteristics suggested that AlgA is an endolytic polyM-specific alginate lyase (EC 4.2.2.3). The products of alginate and polyM degradation by AlgA were purified and identified through fast protein liquid chromatography and electrospray ionization mass spectrometry, which revealed that AlgA mainly produced disaccharides, trisaccharides, and tetrasaccharide from alginate and disaccharides and trisaccharides from polyM. Therefore, the novel lysate AlgA has potential applications in the production of mannuronic oligosaccharides and poly-α-l-guluronate blocks from alginate.

A Novel Bifunctional Endolytic Alginate Lyase with Variable Alginate-Degrading Modes and Versatile Monosaccharide-Producing Properties

Endo-type alginate lyases usually degrade alginate completely into various size-defined unsaturated oligosaccharide products (≥disaccharides), while exoenzymes primarily produce monosaccharide products including saturated mannuronate (M) and guluronate (G) units and particularly unsaturated Δ units. Recently, two bifunctional alginate lyases have been identified as endolytic but M- and G-producing with variable action modes. However, endolytic Δ-producing alginate lyases remain undiscovered. Herein, a new Flammeovirga protein, Aly2, was classified into the polysaccharide lyase 7 superfamily. The recombinant enzyme and its truncated protein showed similar stable biochemical characteristics. Using different sugar chains as testing substrates, we demonstrated that the two enzymes are bifunctional while G-preferring, endolytic whereas monosaccharide-producing. Furthermore, the catalytic module of Aly2 can vary the action modes depending on the terminus type, molecular size, and M/G content of the substrate, thereby yielding different levels of M, G, and Δ units. Notably, the enzymes preferentially produce Δ units when digesting small size-defined oligosaccharide substrates, particularly the smallest substrate (unsaturated tetrasaccharide fractions). Deletion of the non-catalytic region of Aly2 caused weak changes in the action modes and biochemical characteristics. This study provided extended insights into alginate lyase groups with variable action modes for accurate enzyme use.

Structural basis for controlling the enzymatic properties of polymannuronate preferred alginate lyase FlAlyA from the PL-7 family

Alginate-recognition subsites of alginate lyase FlAlyA were characterized as potential targets for engineering alginate oligosaccharides that are useful biomaterials.

Laminarinase from Flavobacterium sp. reveals the structural basis of thermostability and substrate specificity

Laminarinase from Flavobacterium sp. strain UMI-01, a new member of the glycosyl hydrolase 16 family of a marine bacterium associated with seaweeds, mainly degrades β-1,3-glucosyl linkages of β-glucan (such as laminarin) through the hydrolysis of glycosidic bonds. We determined the crystal structure of ULam111 at 1.60-Å resolution to understand the structural basis for its thermostability and substrate specificity. A calcium-binding motif located on the opposite side of the β-sheet from catalytic cleft increased its degrading activity and thermostability. The disulfide bridge Cys31-Cys34, located on the β2-β3 loop near the substrate-binding site, is responsible for the thermostability of ULam111. The substrates of β-1,3-linked laminarin and β-1,3-1,4-linked glucan bound to the catalytic cleft in a completely different mode at subsite -3. Asn33 and Trp113, together with Phe212, formed hydrogen bonds with preferred substrates to degrade β-1,3-linked laminarin based on the structural comparisons. Our structural information provides new insights concerning thermostability and substrate recognition that will enable the design of industrial biocatalysts.

Development of an Analysis Method for 4-Deoxy-l-erythro-5-hexoseulose Uronic Acid by LC/ESI/MS with Selected Ion Monitoring

This study describes a simple and rapid analytical quantitative method for measuring 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH) using liquid chromatography-electrospray ionization-mass spectrometry (LC/ESI/MS). For a chromatographic condition, Shodex IC NI-424 column (4.6 mm i.d. x 100 mm, 5 μm) for anion analysis and an isocratic elution of 40 mM ammonium formate buffer including 0.1% formic acid (pH 3.75) at a flow rate of 0.5 mL/min was used. The column temperature was set to 40°C. In the analysis of DEH produced by exo-type alginate lyase (AlyFRB) from Falsirhodobacter sp. alg1, a peak was detected with a retention time of 3.207 min. The prepared calibration curves for DEH analysis using the selected ion monitoring (SIM) mode of a mass spectrometer revealed a good linear relationship (correlation factor: 0.9998) within the test range (0.1–100 μg/mL). The limits of detection (S/N = 3) and quantification (S/N = 10) for DEH in SIM analysis were 0.008 and 0.027 μg/mL, respectively. Using the developed condition of LC/ESI/MS analysis, separation and detection of alginate unsaturated oligosaccharides were also tested. In an analysis time of about 13 min, this method was able to separate and detect an alginate unsaturated disaccharide, a trisaccharide, and a tetrasaccaride produced by poly(β-D-mannuronate) lyase, respectively. The analysis method established in this study will contribute to the quantitative and qualitative analysis of DEH, and the activity measurement of exo-type alginate lyase.

Identification of 2-keto-3-deoxy-d-Gluconate Kinase and 2-keto-3-deoxy-d-Phosphogluconate Aldolase in an Alginate-Assimilating Bacterium, Flavobacterium sp. Strain UMI-01

Recently, we identified an alginate-assimilating gene cluster in the genome of Flavobacterium sp. strain UMI-01, a member of Bacteroidetes. Alginate lyase genes and a 4-deoxy-l-erythro-5-hexoseulose uronic acid (DEH) reductase gene in the cluster have already been characterized; however, 2-keto-3-deoxy-d-gluconate (KDG) kinase and 2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolase genes, i.e., flkin and flald, still remained uncharacterized. The amino acid sequences deduced from flkin and flald showed low identities with those of corresponding enzymes of Saccharophagus degradans 2-40^T, a member of Proteobacteria (Kim et al., Process Biochem., 2016). This led us to consider that the DEH-assimilating enzymes of Bacteroidetes species are somewhat deviated from those of Proteobacteria species. Thus, in the present study, we first assessed the characteristics in the primary structures of KDG kinase and KDG aldolase of the strain UMI-01, and then investigated the enzymatic properties of recombinant enzymes, recFlKin and recFlAld, expressed by an Escherichia coli expression system. Multiple-sequence alignment among KDG kinases and KDG aldolases from several Proteobacteria and Bacteroidetes species indicated that the strain UMI-01 enzymes showed considerably low sequence identities (15%-25%) with the Proteobacteria enzymes, while they showed relatively high identities (47%-68%) with the Bacteroidetes enzymes. Phylogenetic analyses for these enzymes indicated the distant relationship between the Proteobacteria enzymes and the Bacteroidetes enzymes, i.e., they formed distinct clusters in the phylogenetic tree. recFlKin and recFlAld produced with the genes flkin and flald, respectively, were confirmed to show KDG kinase and KDPG aldolase activities. Namely, recFlKin produced 1.7 mM KDPG in a reaction mixture containing 2.5 mM KDG and 2.5 mM ATP in a 90-min reaction, while recFlAld produced 1.2 mM pyruvate in the reaction mixture containing 5 mM KDPG at the equilibrium state. An in vitro alginate-metabolizing system constructed from recFlKin, recFlAld, and previously reported alginate lyases and DEH reductase of the strain UMI-01 could convert alginate to pyruvate and glyceraldehyde-3-phosphate with an efficiency of 38%.

Proteomic analysis of scallop hepatopancreatic extract provides insights into marine polysaccharide digestion

Marine polysaccharides are used in a variety of applications, and the enzymes that degrade these polysaccharides are of increasing interest. The main food source of herbivorous marine mollusks is seaweed, and several polysaccharide-degrading enzymes have been extracted from mollusk digestive glands (hepatopancreases). Here, we used a comprehensive proteomic approach to examine the hepatopancreatic proteins of the Zhikong scallop (Chlamys farreri). We identified 435 proteins, the majority of which were lysosomal enzymes and carbohydrate and protein metabolism enzymes. However, several new enzymes related to polysaccharide metabolism were also identified. Phylogenetic and structural analyses of these enzymes suggest that these polysaccharide-degrading enzymes may have a variety of potential substrate specificities. Taken together, our study characterizes several novel polysaccharide-degrading enzymes in the scallop hepatopancreas and provides an enhanced view of these enzymes and a greater understanding of marine polysaccharide digestion.

Complete genome sequence and transcriptomic analysis of a novel marine strain Bacillus weihaiensis reveals the mechanism of brown algae degradation

A novel marine strain representing efficient degradation ability toward brown algae was isolated, identified, and assigned to Bacillus weihaiensis Alg07. The alga-associated marine bacteria promote the nutrient cycle and perform important functions in the marine ecosystem. The de novo sequencing of the B. weihaiensis Alg07 genome was carried out. Results of gene annotation and carbohydrate-active enzyme analysis showed that the strain harbored enzymes that can completely degrade alginate and laminarin, which are the specific polysaccharides of brown algae. We also found genes for the utilization of mannitol, the major storage monosaccharide in the cell of brown algae. To understand the process of brown algae decomposition by B. weihaiensis Alg07, RNA-seq transcriptome analysis and qRT-PCR were performed. The genes involved in alginate metabolism were all up-regulated in the initial stage of kelp degradation, suggesting that the strain Alg07 first degrades alginate to destruct the cell wall so that the laminarin and mannitol are released and subsequently decomposed. The key genes involved in alginate and laminarin degradation were expressed in Escherichia coli and characterized. Overall, the model of brown algae degradation by the marine strain Alg07 was established, and novel alginate lyases and laminarinase were discovered.

Engineered yeast whole-cell biocatalyst for direct degradation of alginate from macroalgae and production of non-commercialized useful monosaccharide from alginate

Alginate is a major component of brown macroalgae. In macroalgae, an endolytic alginate lyase first degrades alginate into oligosaccharides. These oligosaccharides are further broken down into monosaccharides by an exolytic alginate lyase. In this study, genes encoding various alginate lyases derived from alginate-assimilating marine bacterium Saccharophagus degradans were isolated, and their enzymes were displayed using the yeast cell surface display system. Alg7A-, Alg7D-, and Alg18J-displaying yeasts showed endolytic alginate lyase activity. On the other hand, Alg7K-displaying yeast showed exolytic alginate lyase activity. Alg7A, Alg7D, Alg7K, and Alg18J, when displayed on yeast cell surface, demonstrated both polyguluronate lyase and polymannuronate lyase activities. Additionally, polyguluronic acid could be much easily degraded by Alg7A, Alg7K, and Alg7D than polymannuronic acid. In contrast, polymannuronic acid could be much easily degraded by Alg18J than polyguluronic acid. We further constructed yeasts co-displaying endolytic and exolytic alginate lyases. Degradation efficiency by the co-displaying yeasts were significantly higher than single alginate lyase-displaying yeasts. Alg7A/Alg7K co-displaying yeast had maximum alginate degrading activity, with production of 1.98 g/L of reducing sugars in a 60-min reaction. This system developed, along with our findings, will contribute to the efficient utilization and production of useful and non-commercialized monosaccharides from alginate by Saccharomyces cerevisiae.