Suhaimi Md Yasir

Cultivation of tropical red seaweeds in the BIMP-EAGA region

The Brunei–Indonesia–Malaysia–Philippines East Asia Growth Area (BIMP-EAGA) is located within the Coral Triangle, known to have the world’s richest biodiversity in marine flora and fauna. This region lies within the 10° N and 10° S of the Equator where natural populations of both Kappaphycus and Eucheuma grow luxuriantly and abundantly. It is in this same region where commercial cultivation of Kappaphycus and Eucheuma began in the Philippines around the mid-1960s. Commercial farming of Kappaphycus (which was originally called Eucheuma) was successful in the Philippines from the early 1970s, after which the technology was transferred to Indonesia and Malaysia in the late 1970s. No seaweed cultivation has been reported in Brunei. At present, carrageenophytes are cultivated in sub-tropical to tropical countries circumferentially around the globe within the 10° N and S of the Equator. However, their combined production is still low as compared to Indonesia, the Philippines, and Malaysia. Notably, few improvements in farming techniques have been made since its first introduction. Some of the major improvements were the introduction of deep-water farming using hanging long lines, multiple rafts, and spider webs in the Philippines; the use of short and long ‘loops’, instead of plastic ‘tie-tie’ in Indonesia; and mechanization in harvesting and use of solar “greenhouse” drying in Malaysia. Commercial cultivation of tropical red seaweeds in the BIMP-EAGA region is dominated by Kappaphycus and Eucheuma (carrageenophytes) and Gracilaria (agarophytes) and the area became the major region for the production of carageenophytes and agarophytes globally. In particular, Indonesia is a major center for the production of Gracilaria. There is an increasing demand for other agarophytes/carrageenophytes in the international market such as Gelidium spp., Pterocladia spp., Porphyroglossum sp., and Ptilophora sp. for paper and ethanol production in Indonesia and Malaysia, and Halymenia for phycoerythrin pigments in the Philippines currently pursued in an experimental stage. A summary of the present status, problems, sustainability, and challenges for the cultivation of tropical red seaweeds in the BIMP-EAGA region are discussed in this paper.

Kappaphycus alvarezii waste biomass: A potential biosorbent for chromium ions removal

The Cr(III) sorption experiments onto Kappaphycus alvarezii waste biomass were conducted at different pH values (2-6) under the conditions of initial metal concentration of 10-50 mg/L and the chemical compositions of Cr-Cu and Cr-Cd. The Cr(III) sorption capacities were slightly dependent on pH, and the maximum sorption capacity was 0.86 mg/g at pH 3. The sorption capacities increased with increase in the initial metal concentration, whereas it was suppressed by the presence of Cu(II) and Cd(III) in the solution. The Cr(III) sorption equilibrium was evaluated using Langmuir, Freundlich and BET isotherms. The sorption mechanisms were characterised using scanning electron microscopy and Fourier transform infrared spectroscopy. The main mechanisms were ion exchange coupled with a complexation mechanism. Kappaphycus alvarezii waste biomass represents a potential for Cr(III) ion removal from aqueous solution.

Review paper on cell membrane electroporation of Microalgae using Electric Field Treatment Method for Microalgae Lipid extraction

The paper reviews the recent studies on the lipid extraction of microalgae that mainly highlighted on the cell disruption method using variety of microalgae species. Selection of cell disruption method and devices are crucial in order to achieve the highest extraction percentage of lipid and other valuable intracellular (proteins, carotenoids and chlorophylls) from microalgae cell. Pulsed electric field (PEF) and electrochemical lysis methods were found to be potential for enhancing the extraction efficiencies either conducted in single step extraction or used as pre-treatment followed by conventional extraction method. The PEF technology capable to extract lipid as high as 75%. While, electrochemical lysis treatment capable to extract lipid approximately 93% using Stainless Steel (SS) and Ti/IrO2 as the cathode and anode electrode respectively. PEF technology and electrochemical lysis are still considered to be a new method for microalgae lipid extraction and further investigation can still be done for better improvement of the system.

Evaluation of growth rate and semi‐refined carrageenan properties of tissue‐cultured Kappaphycus alvarezii (Rhodophyta, Gigartinales)

This study aimed to evaluate and compare the quality of κ‐carrageenan obtained from tissue‐cultured and field‐cultured Kappaphycus alvarezii. Carrageenan properties including yield, viscosity, gel strength and sulfate content were studied. After 60 days of cultivation, tissue‐cultured K. alvarezii showed a higher growth rate (6.3 ± 0.01% day−1) than field‐cultured seedlings (3.4 ± 0.3% day−1). The obtained carrageenan yield from tissue‐cultured (67.3 ± 16.4%) was higher than field‐cultured K. alvarezii (51.5 ± 21.0%). Gel viscosity of carrageenans from tissue‐cultured K. alvarezii (1280.0 ± 25.0 cP) was found significantly higher than field‐cultured samples (87.8 ± 20.9 cP). The 1.5% gel solution of tissue‐cultured and field‐cultured K. alvarezii exhibited gel strengths of 703.5 ± 14.1 and 288.3 ± 19.3 g cm−2, respectively. The average sulfate content of carrageenans was found to be significantly different between tissue‐cultured and field‐cultured K. alvarezii with 34.2 ± 10.9 and 7.5 ± 6.7%, respectively. Tissue culture is recommended to produce high quality seedlings by providing optimized culture conditions to the seaweed. This approach can serve as an alternative way to solve the seedling shortage problems currently faced by the seaweed industry.

Review: Pre-treatments and Fermentation of Seaweed for Bioethanol Production

This article reviews the current studies on the production of bioethanol from seaweed with a focus on the process pre-treatments and variety of microorganisms used in the process. Pre-treatment selection is essential to maximize the amount of reduced sugar for the fermentation to produce bioethanol. Specific microbial strains are matched to their ability to utilize sugar sources. Some studies focus mainly on general processing with variable microbial strains to gauge their abilities in fermentation. A summary of the current studies was carried out, and it is evident that two or more yield increasing techniques can coexist within a single process. The integration of the findings may be the key to make seaweed fermentation more efficient and affordable to serve as a sustainable and renewable energy source.

The Cultivation of Kappaphycus and Eucheuma in Tropical and Sub-Tropical Waters

Kappaphycus and Eucheuma species have been successfully cultivated in Southeast Asia since the early 1970s. The increasing global demand for carrageenan in processed foods and thereby the need for industrial-scales of biomass to be provided to feed an extraction industry, exceeded wild stock availability and productivity and commercial demands could only be achieved through extensive cultivation of selected carrageenophytes. This unprecedented situation led to the introduction of carrageenophyte species and cultivars around the world; combined production of Eucheuma and Kappaphycus is one of the largest for seaweed biomass in the world.

Implications of drying temperature and humidity on the drying kinetics of seaweed

A Low Temperature and Humidity Chamber Test tested in the Solar Energy Laboratory, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, Malaysia. Experiments are attempted to study the effect of drying air temperature and humidity on the drying kinetics of seaweed Kappaphycus species Striatum besides to develop a model to estimate the drying curves. Simple method using a excel software is used in the analysis of raw data obtained from the drying experiment. The values of the parameters a, n and the constant k for the models are determined using a plot of curve drying models. Three different drying models are compared with experiment data seaweed drying at 30, 40, 50 and 60°C and relative humidity 20, 30 and 40% for seaweed. The higher drying temperatures and low relative humidity effects the moisture content that will be rapidly reduced. The most suitable model is selected to best describe the drying behavior of seaweed. The values of the coefficient of determination (R2), mean bias error (MBE) and root mean square error (RMSE) are used to determine the goodness or the quality of the fit. The Page model is showed a better fit to drying seaweed. The results from this study crucial for solar dryer development on pilot scale in Malaysia.

Post-Harvest Handling of Eucheumatoid Seaweeds

The post-harvest handling of cultivated seaweed biomass is a crucial stage in the whole value-chain of the carrageenophyte industry. The quantity and quality of carrageenan derived from any given biomass depends largely on the post-handling treatment and management of the supply-chain for the harvested seaweeds. Since the successful farming of Kappaphycus and Eucehuma began in the early 1970s in the Philippines, the generally low technologies and cheaper conventional methods of drying the harvested seaweeds (i.e. hanging, platform, shade drying, ‘sauna-like method,’ etc.) are still prefered by the majority of farmers. However, these methods pose serious problems for carrageenophyte quality. A new day is coming when the traditional methods will not be sufficient in order to add value to the biomass. Recently, new methods for the drying of various eucheumatoid seaweeds were introduced, e.g. passive drying (chimney and greenhouse-based solar houses), active drying (de-humidifier drier) and hybrid (wind turbine, double-pass solar collectors with fins and v-groove, solar driers). However, these are still in their early stages of development and technology transfer to the industry.

Comparative studies on the alcohol types presence in Gracilaria sp. and rice fermentation using Sasad

Alternative fuel sources such as biofuels are needed in order to overcome environmental problem caused by fossil fuel consumption. Currently, most biofuel are produced from land based crops and there is a possibility that marine biomass such as macroalgae can be an alternative source for biofuel production. The carbohydrate in macroalgae can be broken down into simple sugar through thermo-chemical hydrolysis and enzymatic hydrolysis. Dilute-acid hydrolysis was believed to be the most available and affordable method. However, the process may release inhibitors which would affect alcohol yield from fermentation. Thus, this work was aimed at investigating if it is possible to avoid this critical pre-treatment step in macroalgae fermentation process by using Sasad, a local Sabahan fermentation agent and to compare the yield with rice wine fermentation. This work hoped to determine and compare the alcohol content from Gracilaria sp. and rice fermentation with Sasad. Rice fermentation was found containing ethanol and 2 - methyl - 1 - propanol. Fermentation of Gracilaria sp. had shown the positive presence of 3 - methyl - 1 - butanol. It was found that Sasad can be used as a fermentation agent for bioalcohol production from Gracilaria sp. without the need for a pretreatment step. However further investigations are needed to determine if pre-treatment would increase the yield of alcohol.

Effect of varying acid hydrolysis condition in Gracilaria sp. fermentation using sasad

Macroalgae or seaweed is being considered as promising feedstock for bioalcohol production due to high polysaccharides content. Polysaccharides can be converted into fermentable sugar through acid hydrolysis pre-treatment. In this study, the potential of using carbohydrate-rich macroalgae, Gracilaria sp. as feedstock for bioalcohol production via various acid hydrolysis conditions prior to the fermentation process was investigated and evaluated. The seaweed used in this research was from the red algae group, using species of Gracilaria sp. which was collected from Sg. Petani Kedah, Malaysia. Pre-treatment of substrate was done using H2SO4 and HCl with molarity ranging from 0.2M to 0.8M. The pretreatment time were varied in the range of 15 to 30 minutes. Fermentation was conducted using Sasad, a local Sabahan fermentation agent as a starter culture. Alcohol extraction was done using a distillation unit. Reducing sugar analysis was done by Benedict test method. Alcohol content analysis was done using specific gravity test. After hydrolysis, it was found out that acid hydrolysis at 0.2M H2SO4 and pre-treated for 20 minutes at 121°C has shown the highest reducing sugar content which has yield (10.06 mg/g) of reducing sugar. It was followed by other samples hydrolysis using 0.4M HCl with 30 minutes pre-treatment and 0.2M H2SO4, 15 minutes pre-treatment with yield of 8.06 mg/g and 5.75 mg/g reducing sugar content respectively. In conclusion, acid hydrolysis of Gracilaria sp. can produce higher reducing sugar yield and thus it can further enhance the bioalcohol production yield. Hence, acid hydrolysis of Gracilaria sp. should be studied more as it is an important step in the bioalcohol production and upscaling process.