Raw Seaweed Research Articles

Enhancing water resistance and mechanical properties of starch‐based edible biofilms through chitosan, seaweed, and sodium tripolyphosphate modifications

AbstractThe widespread use of single‐use plastic food wrapping and drinking straws has led to significant plastic and microplastic pollution, threatening environmental sustainability and human health. This study aims to provide sustainable alternatives by improving starch‐based biofilms' mechanical properties and water resistance for food wrapping and edible drinking straws. We modified starch with chitosan, raw seaweed, and sodium tripolyphosphate (STPP) to enhance these biofilms. Our results show that the optimal proportion of chitosan, combined with varying seaweed and STPP content, significantly improves the biofilms' properties. The developed starch‐based biofilms offer an eco‐friendly and sustainable alternative to single‐use plastic, with the potential for large‐scale, cost‐effective production.Highlights Novel edible starch‐based biofilms were successfully prepared. The biofilms made from renewable FDA‐approved edible materials. Biofilms showed improved mechanical properties and water resistance. The biofilms exhibited non‐toxic and antimicrobial properties. Biofilms offer alternatives to single‐use plastic for food wrapping.

Characterization of Biodegradable Films from Raw Seaweed (Kappaphycus Alvarezii) and Glycerol

Abstract To reduce the use of plastic, innovation is needed to make packaging materials that are environmentally friendly and easy to be degraded. As the main ingredient of this packaging material should be organic materials that are easily obtained. One of the organic materials is seaweed (Kappaphycus Alvarezii) which can be used as raw material for making biodegradable packaging and combined with glycerol. Biodegradable films with nine combinations of seaweed and glycerol were developed to gain the best composition. The yields of these combinations were tested on their tensile strength, elongation, Modulus Young, Water Vapor Permeability, and biodegradability. The Tensile Strength value of the film with 1 gram seaweed and 1 gram glycerol (S1G1) was the highest (22.366±2.148017 MPa), The elongations values of the films with 1.5 g glycerol and 2 g seaweed (18.99217±2.442663%) were highest significantly. The water vapor permeability (WVP) and the thickness of the composite films increased due to the increase of seaweed and glycerol amounts respectively. The biodegradability increased if the seaweed amounts decreased, but it increased if the glycerol amounts increased as well.

Chemometric models for high-throughput biomass grading of the kelp Ecklonia radiata, using mid-infrared (MIR) and near-infrared (NIR) spectroscopy

The kelp Ecklonia radiata is a target species for aquaculture in the southern hemisphere, but the biomass quality varies both spatially and temporally, making high-throughput chemometric methods essential for biomass grading. We built partial least squares regression models and partial least squares discriminant analysis models using mid-infrared and near-infrared spectroscopy, based on 162 calibration samples and 24 validation samples. The near-infrared models generally outperformed the mid-infrared models based on both predictions and sensitivity to outliers. Near-infrared partial least squares regression models were highly accurate for predicting glucose, alginate, phlorotannins, and carbon content (relative prediction error < 8 %) and the near-infrared partial least squares discriminant analysis model could accurately predict region of origin for Wellington samples (zero false negatives and one false positive). Overall, our results demonstrate that near-infrared and mid-infrared spectroscopy are valuable tools for biomass grading of raw seaweed samples and can be used for establishing provenance.

The Seaweed Supply Chain in Jambiani Coastal Communities, Zanzibar:

The study investigates activities in the supply chain of seaweed and their challenges among seaweed farmers in the coastal community of Jambiani-Zanzibar. The study is conducted in Zanzibar's Jambiani area with greater concentration in Kikadini and Kibigija. Employing qualitative approaches, the case study design is chosen to be the best fit in to this study considering the case, respondents and nature of the study. Researchers recruit 45 respondents through snowball and purposive techniques. To obtain the required data, researchers make use of In-Depth Interviews (IDI), focus group Discussions (FGD) and document review. Through tables created manually, researchers code and analyse data content wise. Findings show that the supply chain of seaweed just like other crops involve activities like farming and harvesting, storage and preservation, value and quality addition well as marketing. However, seaweed farmers were confronted by challenges include low price, lack of proper storage facilities, farming and harvesting facilities, climatic changes among others. Thus, based on the observed findings, researchers recommend the establishment of well facilitated drying and storage centres, sufficing farmers with adequate information regarding seaweed market and prices worldwide and establishment of seaweed processing industries which will help in minimizing the act of selling raw seaweed abroad.

SEAWEED CULTURE, POST-HARVEST PROCESSING, AND MARKET GENERATION FOR EMPLOYMENT OF COASTAL POOR COMMUNITIES IN COX'S BAZAR

Seaweed farming is one of the aquaculture industries with the greatest growth rate worldwide, with an annual production of over 33 billion tonnes, and a value of USD$11.8 billion which is predicted to treble by 2024. The current study was conducted in the Bakkhali River estuary and set out to survey the seaweed cultivation, processing, marketing status of the seaweed farmers and evaluate its financial benefits. Gracilaria lemaneiformis and Ulva intestinalis were cultured using the rope methods. The yield of G. lemaneiformis and U. intestinalis was good (Ten 15 m long ropes were used in each of the 45 plots, produced 7770 kg of G. lemaneiformis in the first 15 days while using ten 15 m long ropes were in each of the plots of U. intestinalis produced 2300 kg). Water parameters viz. temperature, salinity, pH, DO and transparency were checked every 15 days. According to previous literature, winter was determined to be the most productive time for seaweed development in Bangladesh. Seaweed was processed by the sun drying method and sold to retail clients, neighborhood shops and markets, and representatives in Cox's Bazar, Bandarban, Rangamati and Khagrachari district, where G. lemaneiformis attracting the higher price. The income of seaweed farmers has increased more than in the previous years to maintain their family. Most of the farmers used raw seaweed as traditional medicine for the treatment of gastric problem (80%), diabetes (5%), blood pressure (3%) and cancer (2%). They also used seaweed as an additive with other vegetables, mutton and chicken. Education for coastal people is very difficult, but after cultivating seaweed, about 60% of farmers can afford their children's education cost and about 85% of the households had electric fans, while the majority had mobile phones. The cost-benefit analysis demonstrated that seaweed cultivation is highly profitable.

Hiện trạng chất lượng rong câu nguyên liệu tại một số tỉnh ven biển phía Bắc

Gracilaria seaweed is the main raw material for the extraction of agar, a widely used polysaccharide in the food industry. The results analysis of raw seaweed samples collected from the May to the June 2021 survey in 11 northern coastal provinces showed that the level of impurities in raw seaweed was quite high, reached 24.8 ± 5.2% dry weight. Agar content in raw seaweed averaged 18.7 ± 2.3% dry weight; agar freezing capacity 243.7 ± 29.6 g/cm2; agar freezing temperature 34.5 ± 0.3oC. The protein content of dry seaweed ranges from 9.38% to 12.75%, lipid - from 1.06% to 1.28%, and inorganic salts - from 20.85% to 22.17%. The results of this analysis also showed that the content and quality of raw seaweed has significantly decreased compared to the past. Therefore, it is necessary to develop solutions to improve the quality of raw seaweed sources in our country in the future to satisfy the needs of domestic production and export.

The Enzyme-Assisted Extraction of compounds of interest in agriculture: Case study of the red seaweed Solieria chordalis (C. Agardh) J. Agardh

For centuries, seaweeds have been spread on fields to improve soil properties and crop yield. Over the last thirty years, the use of seaweed-based extracts has attracted increased attention in agriculture. In comparison with raw seaweed, extracts may be more concentrated in bioactive molecules such as macro/microelements, peptides, polysaccharides and metabolites. These molecules are usually obtained by conventional Water Extraction (WE), which is most often time consuming, with low selectivity and extraction yields. Over the last decade, tailored extraction processes using microwave, ultrasound and enzyme have demonstrated their advantages to obtain enriched seaweed extracts. In this context, the aim is to determine, for the first time in Solieria chordalis, whether Enzyme-Assisted Extraction (EAE) is an effective way of producing extracts enriched in macro/microelements and Plant Growth Regulators (PGRs), which are some of the main compounds of interest for plant nutrition and biostimulation. The red seaweed S. chordalis (C. Agardh) J. Agardh (Gigartinales, Rhodophyta) has been chosen as a case study model since it proliferates on the South Brittany coast (France) during the winter. The extraction yield and biochemical composition of the extracts are determined to assess the efficiency of EAE in comparison with WE. The results demonstrate that EAE increases the contents compared with WE in terms of neutral sugars (×2) and proteins (×1.3). In addition, PGRs in S. chordalis are quantified here for the first time. The most abundant PGRs present in S. chordalis and its extracts are Indole 3-Acetic Acid (IAA), 1-Amino-1-Cyclopropane-Carboxylic Acid (ACC) and Salicylic Acid (SA). Indeed, EAE allow us to enrich the content of the extracts in SA (×3), ACC (×3) and IAA (×6), compared with WE. Therefore, this study demonstrates that EAE is an efficient process for enriching S. chordalis extracts in various compounds, and should be investigated on other seaweeds for agricultural purposes.

Impact of thermal cooking processes on organochlorine pesticide residues (OCPs) in the edible green seaweed, Ulva lactuca, and associated human health risk assessment

Seaweeds are emerging natural food items in different countries. However, they are known to be potentially contaminated by chemical residues. This study examined the impact of domestic cooking methods such as boiling, steaming, and microwave cooking on reduction of organochlorine pesticide (OCP) level in edible green seaweed Ulva lactuca. Thermal cooking processes significantly influences the OCP residues in U. lactuca. The OCP residue concentration decreased after boiling, steaming, and microwave cooking compared to raw seaweed. The total OCP residue concentration in raw seaweed was 0.707 mg/kg, which reduced to 0.168, 0.178, and 0.241 mg/kg after boiling, microwaving, and steam cooking, respectively. Aldrin, endrin, DDT, and endosulfan were predominant OCPs in raw and processed seaweeds. Health risk due to OCP residues was evaluated using food consumption data, acceptable daily intake, and safety indices such as hazard quotient (HQ) and hazard index (HI). The HQ and HI values did not exceed the unit value (HQ, HI < 1), indicating that the level of OCP residues in U. lactuca does not pose any appreciable risk to the consumers. Therefore, the research finding establishes that different thermal cooking processes reduce the OCP residue concentration in U. lactuca.

Interventionist industry policy to support local value-adding: Evidence from the Eastern Indonesian seaweed industry

Indonesia has long considered the use of trade restrictions to encourage the development of domestic value-adding in primary production. In 2015, these were suggested as a strategy to support the development of a national seaweed processing industry, however, such policies were ultimately not implemented on a national level. In August 2022, the eastern Indonesian province of Nusa Tenggara Timor implemented a ban on trade of raw seaweed outside of the province, aiming to increase supply of seaweed to local processors and encourage further investment in local processing capacity, with the ultimate goal of supporting increased value-adding and the development of the local seaweed processing sector. The policy was accompanied by establishment of government mandated price floors for the three seaweed processors located in the province. This article examines the execution and potential implications of this new policy with several findings. First, there is a lack of clarity in the definition of ‘value-adding’ and the types of processing developments that the regulation seeks to incentivise. Second, the province does not consistently have the capacity to process all of the seaweed it produces, exacerbating the negative impacts of trade restrictions on farmers. Third, the purpose of the price floor and its relationship to market prices in other regions is unclear and prevents differentiation by product quality, reducing incentives for farmers to increase production quantities and qualities. Fourth, the province is experiencing difficulty enforcing the seaweed export restrictions such that the ban has incentivized an increase in unofficial seaweed trade out of the province. The article recommends the regulation be revised or revoked and other strategies to support value adding in the region be considered.

Impact of processing pre-treatments on color and the level of heavy metal reduction of the green alga Ulva sp.: A preliminary study

Ulva sp. is an abundant green alga in Gunungkidul waters, Indonesia, considered a source of nourishing food, sought after by food industries. This green alga could be served as a dish, a seasoning, or an ingredient; hence, the assessment of its safety is important. The present study was conducted to reduce heavy metal residues in Ulva sp. collected from Sepanjang beach, Gunungkidul, Indonesia by using two different processing treatments, i.e., washing with citric acid and blanching at various times and seaweed-to-solution ratios. The number of heavy metal residues (As, Cd, Pb, and Hg) was determined by Inductive Coupled Plasma Mass Spectrometry (ICP-MS) and visual green color loss was measured by a color spectrophotometer. The result showed that the concentration of As and Cd in the unprocessed sample was higher than SNI 2690:2015 specification for raw seaweed as well as the National Food and Drug Agency of the Government of Indonesia (BPOM Indonesia) permissible limits in food. Washing Ulva sp. with citric acid 0.5% for 10 min in a seaweed-to-solution ratio of 1:20 could reduce the level of as up to 42.53%, whereas washing Ulva sp. with citric acid 0.5% for 15 min in a seaweed-to-solution of 1:10 could reduce the level of Cd up to 96.12%. All processing treatments affected the appearance of Ulva sp. which is indicated by the increase in color differences (ΔE) > 2.

“Different pretreatments of beach-cast seaweed for biogas production”

The increasing amount of seaweed accumulated in the coasts calls for a proper disposal or treatment in order to reduce secondary pollution effects. Anaerobic digestion of seaweed is a treatment technology that simultaneously produces biogas, supporting the further expansion of the renewable energy production through sustainable bioresources. In this study, three pretreatments (alkaline, hydrothermal and thermo-acidic) were applied on beach-cast seaweed of the Baltic Sea in order to improve the methane yield. The thermo-acidic pretreatment resulted to the highest increase of the methane yield (78% higher than the raw seaweed), while the alkaline pretreatment resulted to a 36% increase of the methane yield and to the highest reduction of the methane production cost compared to raw seaweed based on a preliminary economic assessment. Determination of the different sugars and sugar acids of the seaweed before and after the pretreatments assisted in understanding the effects of each pretreatment on the seaweed matrix. • Beach-cast seaweed was analyzed for its composition in sugars and sugar acids. • A hydrothermal, an alkaline and a thermo-acidic pretreatment was applied. • The thermo-acidic pretreatment resulted to the highest increase of CH 4 yield (78%). • The hydrolysis rate of seaweed was improved by all the pretreatments applied. • Alkaline pretreatment resulted to the lowest cost of CH 4 production from seaweed.

Innovative method to grow the probiotic Lactobacillus reuteri in the omega3-rich microalga Isochrysis galbana

Microalgae are natural sources of valuable bioactive compounds, such as polyunsaturated fatty acids (PUFAs), that show antioxidant, anti-inflammatory, anticancer and antimicrobial activities. The marine microalga Isochrysis galbana (I. galbana) is extremely rich in ω3 PUFAs, mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Probiotics are currently suggested as adjuvant therapy in the management of diseases associated with gut dysbiosis. The Lactobacillus reuteri (L. reuteri), one of the most widely used probiotics, has been shown to produce multiple beneficial effects on host health. The present study aimed to present an innovative method for growing the probiotic L. reuteri in the raw seaweed extracts from I. galbana as an alternative to the conventional medium, under conditions of oxygen deprivation (anaerobiosis). As a result, the microalga I. galbana was shown for the first time to be an excellent culture medium for growing L. reuteri. Furthermore, the gas-chromatography mass-spectrometry analysis showed that the microalga-derived ω3 PUFAs were still available after the fermentation by L. reuteri. Accordingly, the fermented compound (FC), obtained from the growth of L. reuteri in I. galbana in anaerobiosis, was able to significantly reduce the adhesiveness and invasiveness of the harmful adherent-invasive Escherichia coli to intestinal epithelial cells, due to a cooperative effect between L. reuteri and microalgae-released ω3 PUFAs. These findings open new perspectives in the use of unicellular microalgae as growth medium for probiotics and in the production of biofunctional compounds.

Processing and Characterization of Bioplastics from the Invasive Seaweed Rugulopteryx okamurae.

The seaweed Rugulopteryx okamurae, from the Pacific Ocean, is considered an invasive species in the Mediterranean Sea. In this work, the use of this seaweed is proposed for the development of bio-based plastic materials (bioplastics) as a possible solution to the pollution produced by the plastic industry. The raw seaweed Rugulopteryx okamurae was firstly blended with glycerol (ratios: 50/50, 60/40 and 70/30), and subsequently, they were processed by injection molding at a mold temperature of 90, 120 and 150 °C. The rheological properties (frequency sweep tests and temperature ramp tests) were obtained for blends before and after processing by injection molding. The functional properties of the bioplastics were determined by the water uptake capacity (WUC) values and further scanning electron microscopy (SEM). The results obtained indicated that E’ was always greater than E”, which implies a predominantly elastic behavior. The 70/30 ratio presents higher values for both the viscoelastic moduli and tensile properties than the rest of the systems (186.53 ± 22.80 MPa and 2.61 ± 0.51 MPa, respectively). The WUC decreased with the increase in seaweed in the mixture, ranging from 262% for the 50/50 ratio to 181% for the 70/30 ratio. When carrying out the study on molded bioplastic 70/30 at different temperatures, the seaweed content did not exert a remarkable influence on the final properties of the bioplastics obtained. Thus, this invasive species could be used as raw material for the manufacture of environmentally friendly materials processed by injection molding, with several applications such as food packaging, control–release, etc.

Improving bio-oil chemical profile of seaweeds through anaerobic fermentation pre-treatment

Biomass pre-treatments for bio-oil quality improvement are mainly based on thermal and chemical methods which are costly and hence reduce the sustainability of pyrolysis-based refineries. In this paper, anaerobic digestion (AD) and dark fermentation (DF) are proposed as alternative ‘green’ pre-treatments to improve this situation. For this purpose, three seaweeds namely Sargassum polycystum, (Phaephyta), Gracilaria tenuistipitata, (Rhodophyta) and Ulva reticulata, (Chlorophyta) with high ash and oxygen contents were pre-treated to improve their composition and structure prior to pyrolysis. The results reveal that both biological pre-treatments affected, positively, the composition and structure of the seaweed biomass with AD pre-treatment reducing N and S contents by 86% and 63%, respectively. DF was more efficient in terms of ash and moisture reduction with 25% and 70%, respectively. In addition, oxygen (O) reduction by 27% was observed after DF which was evidenced by FTIR spectroscopy indicating the reduction of most oxygen-containing functional groups in the biomass. On the other hand, the carbon (C) content increased in DF pre-treated seaweeds up to 42%, almost two times higher relative content than C in the raw seaweed. The changes in the composition of pre-treated seaweeds resulted in changes in their thermal degradation and the volatile profiles produced during pyrolysis. Interestingly, anhydrosugars and furans which account for some 70% (by area) in raw seaweeds markedly declined or become undetectable after DF pre-treatment and correspondingly more acetic acid and hydrocarbons were produced while after AD more aromatics with high toluene content (ca.17%) were generated. The results indicate that bio-oil with profiles more similar to petroleum-based composition i.e. rich in hydrocarbons and low in anhydrosugars, N and S can be generated by AD and DF pre-treatments and opens up the possibility of these approaches to effect cost reduction in the overall generation of bio-based fuels.

Hydrothermal Carbonization (HTC) of Seaweed (Macroalgae) for Producing Hydrochar

Waste seaweed that is collected at coastal regions of maritime provinces in Canada is creating ecological problems as it promotes an anoxic event, which produces nearly zero dissolved oxygen in water along with hydrogen sulfide emission. The work done in this study attempts to address this issue by producing a coal-like solid hydrochar and nutritious liquid slurry (processed water) by employing a rather recent thermo-chemical process called hydrothermal carbonization (HTC) on the seaweed. The HTC was carried out in a batch reactor system for three different reaction temperatures, 180 °C, 200 °C, 220 °C, and three different reaction times, 30, 60, and 120 min. Each of the produced hydrochars was characterized by different analytical methods. The effects of the process conditions on the yield and the properties of the hydrochar and process water were examined. The hydrochar produced at 220 °C and 120 min showed the highest carbon content (48.5%) and heating value (18.93 MJ/kg). The energy density and carbon to nitrogen (C/N) ratio in the hydrochar increased significantly as compared to raw seaweed. Moreover, HTC reduced the ash yield and volatile compounds of the seaweed. Thus, hydrochar can be used as a fuel for direct combustion, in soil remediation, or in carbon sequestration applications.

Determination of nutrition contents based on raw seaweed: economic improvement efforts in Dolly ex-prostitution area

The effort to change Dolly and Jarak's image as an ex prostitution area that was once famous and largest in Southeast Asia in the villages of Putat Jaya, Sawahan District, Surabaya City, has never been done. Making the Dolly and Jarak areas as a tourist village that is capable of supporting and sustaining the economy, is the dream of all citizens and the Surabaya City Government. However, the effort must be thoroughly pursued and patented so that it can be realized and fulfilled. At the Research-based Community Service this time, the service strives to diversify practical, healthy and hygienic seaweed products. There is information on nutrient levels and the great benefits of consuming various processed seaweed.

Determination of combustion characteristics and kinetic parameters of Ulva lactuca and its biochar

Utilization of macroalgae, which accumulated in the coastal area and considered as waste by municipals, for biofuel production is a good solution putting forward for both waste management and meeting the renewable energy requirement. This study aims to investigate the use of Ulva lactuca collected from the Marmara Sea coast as a raw material for solid biofuel production. Therefore, in this study, the combustion characteristics of Ulva lactuca and its biochar were investigated by the thermogravimetric method, and kinetic parameters were determined by using Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods. When the obtained thermograms are examined, it was observed that the combustion of raw seaweed occurs in three phases, while the combustion of biochars occurs in two phases. As a result of the calculations, the combustion activation energies of macroalga and its biochar were found to be approximately 261 kJ/mol and 146 kJ/mol, respectively, using the KAS method. It was found that the values calculated using the FWO method were similar to the KAS method. These data show that biochar requires less energy than raw algae during combustion.

Protein solubility is increased by antioxidant addition during protein extraction from the green macroalga, Ulva sp.

Ulva sp. is a cosmopolitan green macroalga with fast growth and a well-balanced amino acid composition, making it an interesting potential protein resource. Generally, the protein digestibility in unprocessed raw seaweed is low, which is why extraction and concentration of the protein is needed. During protein extraction from fresh Ulva sp. using double screw pressing, sulfite was added as antioxidant in order to increase protein quality by inhibiting oxidative reactions. By pressing, 13–14% of the total biomass protein was extracted. Isoelectric precipitation at pH 2 resulted in a yield of 36% of the extracted protein corresponding to 5% of the total protein, independent on sulfite treatment. However, size exclusion chromatography showed that sulfite addition resulted in a higher amount of native state Rubisco protein. This was explained by inhibited redox enzyme activity and improved polyphenol levels, suggesting prevention of polyphenol-protein crosslinking, resulting in higher amount of soluble protein and improved protein quality.

Integrated valorization of Sargassum muticum in biorefineries

Marine macroalgae represent an excellent raw material for the production of bioactives, adsorbents, plant biostimulants, soil fertilizers and biogas. The success in the exploitation of seaweeds depends on their characteristics, and the approach used to separate their specific active components. In the context of circular economy, invasive species are a good candidate for exploitation, and biorefinery a key valorization technique. Here we investigate a novel biorefinery scheme for an integral valorization of Sargassum muticum. An initial pressing stage allowed the production of a Sap fraction, which showed potential as a plant biostimulant, increasing both root development and shoot/root ratio, especially when used at a dose of 0.1 g/L lyophilized Sap. The solids after pressing were processed by non isothermal autohydrolysis, using pressurized hot water (up to 120-210 °C), a process previously optimized to solubilize the fucoidan and phlorotannin fractions. The residual solids remaining after pressing and autohydrolysis stages were evaluated for the production of biogas. The obtained value (150 mL CH4/g residual solids at 150 °C) was significantly higher than that found for the raw seaweed. The optimal autohydrolysis temperature (150 °C) is compatible with the production of the fucoidan fraction, although the phenolic content is favoured under more severe operation conditions. We also discuss the possibility of preparing adsorbents for pollutant removal and mineral amendments from the autohydrolysis waste solids.

Hydrolyzing Laminaria japonica with a combination of microbial alginate lyase and cellulase

A novel seaweed-hydrolyzing strain designated as Pseudoalteromonas sp. Alg6B was isolated from the surface of brown seaweed (Laminaria japonica). The activity of crude alginate lyase produced by Alg6B was 54.5 U/ml and the main products of hydrolyzing alginate were disaccharide and tetrasaccharide. The hydrolysis rate of seaweed reached up to 97% after combining 3% (v/v) Alg6B and 0.2% (w/v) solid cellulase. In kelp hydrolysate, the contents of nutrients are much more than raw seaweed. Alg6B grows quickly and has the ability of producing alginate oligosaccharides with low molecular weight (MW) (≤2 kDa). Furthermore, this study demonstrates that a combination of microbial alginate lyase and cellulase could almost hydrolyze seaweed completely. This research indicated that Alg6B could provide a feasible pathway to produce alginate oligosaccharides (AOS), and the synergistic effect of alginate lyase and cellulase on seaweed bioconversion can potentially pave the way to the sustainable production of seaweed fertilizer.