Thermal co-processing of lignocellulosic and aquatic biomass, such as algae and shellfish waste, has shown synergistic effects in producing value-added energy products with higher process efficiency than the traditional method, highlighting the importance of scaling up to pilot-scale operations. This article discusses the design and operation of pilot-scale reactors for torrefaction, pyrolysis, and gasification, as well as the key parameters of co-processing biomass into targeted and improved quality products for use as fuel, agricultural application, and environmental remediation. Techno-economic analysis reveals that end product selling price, market dynamics, government policies, and biomass cost are crucial factors influencing the sustainability of thermal co-processing as a feasible approach to utilize the biomass. Because of its simplicity, pyrolysis allows greater energy recovery, while gasification has the highest net present value (profitability). Integration of liquefaction, hydrothermal, and fermentation pre-treatment technology has the potential to increase energy efficiency while reducing process residues.
The recurrent environmental and economic issues associated with the diminution of fossil fuels are the main impetus towards the conversion of agriculture, aquaculture and shellfish biomass and the wastes into alternative commodities in a sustainable approach. In this review, the recent progress on recovering and processing these biomass and waste feedstocks to produce a variety of value-added products via various valorisation technologies, including hydrolysis, extraction, pyrolysis, and chemical modifications are presented, analysed, and discussed. These technologies have gained widespread attention among researchers, industrialists and decision makers alike to provide markets with bio-based chemicals and materials at viable prices, leading to less emissions of CO2 and sustainable management of these resources. In order to echo the thriving research, development and innovation, bioresources and biomass from various origins were reviewed including agro-industrial, herbaceous, aquaculture, shellfish bioresources and microorganisms that possess a high content of starch, cellulose, lignin, lipid and chitin. Additionally, a variety of technologies and processes enabling the conversion of such highly available bioresources is thoroughly analysed, with a special focus on recent studies on designing, optimising and even innovating new processes to produce biochemicals and biomaterials. Despite all these efforts, there is still a need to determine the more cost-effective and efficient technologies to produce bio-based commodities.
Aquatic weeds pose hazards to aquatic ecosystems and particularly the aquatic environment in shellfish aquaculture due to its excessive growth covering entire freshwater bodies, leading to environmental pollution particularly eutrophication intensification, water quality depletion and aquatic organism fatality. In this study, pyrolysis of six aquatic weed types (wild and cultured species of Salvinia sp., Lemna sp. and Spirodella sp.) were investigated to evaluate its potential to reduce and convert the weeds into value-added chemicals. The aquatic weeds demonstrated high fixed carbon (8.7-47.3 wt%), volatile matter content (39.0-76.9 wt%), H/C ratio (1.5-2.0) and higher heating value (6.6-18.8 MJ/kg), representing desirable physicochemical properties for conversion into biofuels. Kinetic analysis via Coats-Redfern integral method obtained different orders for chemical reaction mechanisms (n = 1, 1.5, 2, 3), activation energy (55.94-209.41 kJ/mol) and pre-exponential factor (4.08 × 104-4.20 × 1017 s-1) at different reaction zones (zone 1: 150-268 °C, zone 2: 268-409 °C, zone 3: 409-600 °C). The results provide useful information for design and optimization of the pyrolysis reactor and establishment of the process condition to dispose this environmentally harmful species.
Global production of shellfish aquaculture is steadily increasing owing to the growing market demands for shellfish. The intensification of shellfish aquaculture to maximize production rate has led to increased generation of aquaculture waste streams, particularly the effluents and shellfish wastes. If not effectively managed, these wastes could pose serious threats to human health and the ecosystem while compromising the overall sustainability of the industry. The present work comprehensively reviews the source, composition, and environmental implications of shellfish wastes and aquaculture wastewater. Moreover, recent advancements in the valorization of shellfish wastes into value-added biochar via emerging thermochemical and modification techniques are scrutinized. The utilization of the produced biochar in removing emerging pollutants from aquaculture wastewater is also discussed. It was revealed that shellfish waste-derived biochar exhibits relatively higher adsorption capacities (300-1500 mg/g) compared to lignocellulose biochar (<200 mg/g). The shellfish waste-derived biochar can be effectively employed for the removal of various contaminants such as antibiotics, heavy metals, and excessive nutrients from aquaculture wastewater. Finally, future research priorities and challenges faced to improve the sustainability of the shellfish aquaculture industry to effectively support global food security are elaborated. This review envisages that future studies should focus on the biorefinery concept to extract more useful compounds (e.g., carotenoid, chitin) from shellfish wastes for promoting environmental-friendly aquaculture.
In the Southeast Asian region, the Philippines and Malaysia are two of the most affected by Harmful Algal Blooms (HABs). Using long-term observations of HAB events, we determined if these are increasing in frequency and duration, and expanding across space in each country. Blooms of Paralytic Shellfish Toxin (PST)-producing species in the Philippines did increase in frequency and duration during the early to mid-1990s, but have stabilized since then. However, the number of sites affected by these blooms continue to expand though at a slower rate than in the 1990s. Furthermore, the type of HABs and causative species have diversified for both toxic blooms and fish kill events. In contrast, Malaysia showed no increasing trend in the frequency of toxic blooms over the past three decades since Pyrodinium bahamense was reported in 1976. However, similar to the Philippines, other PST producers such as Alexandrium minutum and Alexandrium tamiyavanichii have become a concern. No amnesic shellfish poisoning (ASP) has been confirmed in either Philippines or Malaysia thus far, while ciguatera fish poisoning cases are known from the Philippines and Malaysia but the causative organisms remain poorly studied. Since the 1990s and early 2000s, recognition of the distribution of other PST-producing species such as species of Alexandrium and Gymnodinium catenatum in Southeast Asia has grown, though there has been no significant expansion in the known distributions within the last decade. A major more recent problem in the two countries and for Southeast Asia in general are the frequent fish-killing algal blooms of various species such as Prorocentrum cordatum, Margalefidinium polykrikoides, Chattonella spp., and unarmored dinoflagellates (e.g., Karlodinium australe and Takayama sp.). These new sites affected and the increase in types of HABs and causative species could be attributed to various factors such as introduction through mariculture and eutrophication, and partly because of increased scientific awareness. These connections still need to be more concretely investigated. The link to the El Niño Southern Oscillation (ENSO) should also be better understood if we want to discern how climate change plays a role in these patterns of HAB occurrences.
Gymnodinium catenatum is a cosmopolitan, bloom-forming dinoflagellate known to produce a suite of potent paralytic shellfish poisoning (PSP) toxins. Here, we revisit two major blooms of G. catenatum along the Fujianese Coast, China, in 2017 and 2018. The impact area of the 2017 bloom was larger than that of the 2018 event. Field sampling and remote satellite sensing revealed that alongshore transport driven by the southwest wind, as well as physical accumulation driven by the northeast wind, played important roles in the development and distribution of the two bloom events. The relationship between wind-induced hydrodynamic conditions and the unprecedented HAB events established in this study adds greatly to our understanding of algal bloom dynamics along the Fujianese coast. These results improve our ability to detect, track, and forecast G. catenatum blooms, thereby potentially minimizing the negative impacts of future HAB events.
Chitin, being the second most abundant biopolymer after cellulose, has been gaining popularity since its initial discovery by Braconot in 1811. However, fundamental knowledge and literature on chitin and its derivatives from insects are difficult to obtain. The most common and sought-after sources of chitin are shellfish (especially crustaceans) and other aquatic invertebrates. The amount of shellfish available is obviously restricted by the amount of food waste that is allowed; hence, it is a limited resource. Therefore, insects are the best choices since, out of 1.3 million species in the world, 900,000 are insects, making them the most abundant species in the world. In this review, a total of 82 samples from shellfish-crustaceans and mollusks (n = 46), insects (n = 23), and others (n = 13)-have been collected and studied for their chemical extraction of chitin and its derivatives. The aim of this paper is to review the extraction method of chitin and chitosan for a comparison of the optimal demineralization and deproteinization processes, with a consideration of insects as alternative sources of chitin. The methods employed in this review are based on comprehensive bibliographic research. Based on previous data, the chitin and chitosan contents of insects in past studies favorably compare and compete with those of commercial chitin and chitosan-for example, 45% in Bombyx eri, 36.6% in Periostracum cicadae (cicada sloughs), and 26.2% in Chyrysomya megacephala. Therefore, according to the data reported by previous researchers, demonstrating comparable yield values to those of crustacean chitin and the great interest in insects as alternative sources, efforts towards comprehensive knowledge in this field are relevant.
Several of the coastal zones in Sabah, Malaysia, are isolated and inaccessible. This study aimed to review the published literature on the health status of the coastal communities in Sabah. The following four main health issues were found: (i) malaria, (ii) tuberculosis (TB), (iii) seafood poisoning, and (iv) antenatal problems. Factors associated with the risk of acquiring malarial infection in the studied coastal area were advanced age, male sex, farming as an occupation, history of travel outside the village, and rainy seasons. TB infection was primarily observed in adult men. Seafood poisoning was significantly common in Sabah. Studies have reported that tetrodotoxin and paralytic shellfish poisoning were commonly reported (30-60 cases annually). Several pregnant women in the coastal community had insufficient knowledge of the national antenatal care programme. Nonetheless, 99% of them received antenatal care at public healthcare facilities with 92% of them undergoing safe delivery. Nevertheless, a majority of the pregnant women had iodine deficiency due to low iodised salt intake. Findings from this review highlighted that the coastal communities in Sabah are experiencing significant health problems. Specific attention is required to significantly enhance the health and well-being of the individuals living in the coastal communities in Sabah.
The lagoon of Setiu Wetlands has high biodiversity of bivalve’s species. The majority of villagers are fisherman and bivalves are one of their income-generating activities. Studies on parasites of bivalves are important to our knowledge for maintenance of natural resources. This study investigated the parasite prevalence among four commercially exploited shellfish species from Setiu Wetland, Malaysia. A total of 120 samples were collected during the low tide time for four shellfish species which were Polymesoda expansa, Meretrix meretrix, Anadara sp. and Crassostrea iredalei. The bivalve specimens were measured on its length with and without shell, width, height, weight and microscopically examined on the presence of parasites focused at gills, muscle and digestive tract. The discovered macroparasite were fixed into 70% ethanol solution for preservation. In this study, Anadara sp. was highest infestation of parasites, while Polymesoda expansa has the least infestation of parasites. There were occurrence of copepod and Nematopsis sp. in Anadara sp., M. meretrix and C. iredalei. Apart from that, there were other parasites observed in four bivalve species such as metacercaria, cestode larvae, Panopeus sp., Pinnotheres sp., Balanus sp. and unidentified ciliates. Ecological factors, feeding activity, season and abundance of definitive host were known to be elements that altered the prevalence of parasites in host. Upon the observation, a high prevalence of Nematopsis sp. were observed in three species of bivalves except P. expansa. Whereas for other parasites were occurred in low prevalence and intensity, without causing significant damage towards host.
Species of the benthic dinoflagellate Gambierdiscus produce polyether neurotoxins that caused ciguatera fish/shellfish poisoning in human. The toxins enter marine food webs by foraging of herbivores on the biotic substrates like macroalgae that host the toxic dinoflagellates. Interaction of Gambierdiscus and their macroalgal substrate hosts is believed to shape the tendency of substrate preferences and habitat specialization. This was supported by studies that manifested epiphytic preferences and behaviors in Gambierdiscus species toward different macroalgal hosts. To further examine the supposition, a laboratory-based experimental study was conducted to examine the growth, epiphytic behaviors and host preferences of three Gambierdiscus species towards four macroalgal hosts over a culture period of 40 days. The dinoflagellates Gambierdiscus balechii, G. caribaeus, and a new ribotype, herein designated as Gambierdiscus type 7 were initially identified based on the thecal morphology and molecular characterization. Our results showed that Gambierdiscus species tested in this study exhibited higher growth rates in the presence of macroalgal hosts. Growth responses and attachment behaviors, however, differed among different species and strains of Gambierdiscus over different macroalgal substrate hosts. Cells of Gambierdiscus mostly attached to substrate hosts at the beginning of the experiments but detached at the later time. Localized Gambierdiscus-host interactions, as demonstrated in this study, could help to better inform efforts of sampling and monitoring of this benthic toxic dinoflagellate.
The concentration of nine trace elements were analyzed in the different tissue organs of commonly available crabs (Portunus sanguinolentus, Portunus pelagicus and Scylla serrate) and bivalve (Polymesoda erosa) species collected from the Miri coast, Borneo in order to evaluate the potential health risk by consumption of these aquatic organisms. Among the analyzed organs, metal accumulation was higher in the gill tissues. The essential (Cu and Zn) and non-essential (Pb and Cd) elements showed the highest (i.e. Zn) and lowest concentrations (i.e. Cd) in their tissue organs, respectively. The estimated daily intake and hazard indices of all metals in the muscle indicate that the measured values were below the provisional tolerable daily intake suggested by the joint FAO/WHO Expert Committee on Food Additives. Compared to Malaysian and international seafood guideline values the results obtained from the present study are lower than the permissible limits and safe for consumption.
Some diatoms of the genera Pseudo-nitzschia and Nitzschia produce the neurotoxin domoic acid (DA), a compound that caused amnesic shellfish poisoning (ASP) in humans just over 30 years ago (December 1987) in eastern Canada. This review covers new information since two previous reviews in 2012. Nitzschia bizertensis was subsequently discovered to be toxigenic in Tunisian waters. The known distribution of N. navis-varingica has expanded from Vietnam to Malaysia, Indonesia, the Philippines and Australia. Furthermore, 15 new species (and one new variety) of Pseudo-nitzschia have been discovered, bringing the total to 52. Seven new species were found to produce DA, bringing the total of toxigenic species to 26. We list all Pseudo-nitzschia species, their ability to produce DA, and show their global distribution. A consequence of the extended distribution and increased number of toxigenic species worldwide is that DA is now found more pervasively in the food web, contaminating new marine organisms (especially marine mammals), affecting their physiology and disrupting ecosystems. Recent findings highlight how zooplankton grazers can induce DA production in Pseudo-nitzschia and how bacteria interact with Pseudo-nitzschia. Since 2012, new discoveries have been reported on physiological controls of Pseudo-nitzschia growth and DA production, its sexual reproduction, and infection by an oomycete parasitoid. Many advances are the result of applying molecular approaches to discovering new species, and to understanding the population genetic structure of Pseudo-nitzschia and mechanisms used to cope with iron limitation. The availability of genomes from three Pseudo-nitzschia species, coupled with a comparative transcriptomic approach, has allowed advances in our understanding of the sexual reproduction of Pseudo-nitzschia, its signaling pathways, its interactions with bacteria, and genes involved in iron and vitamin B12 and B7 metabolism. Although there have been no new confirmed cases of ASP since 1987 because of monitoring efforts, new blooms have occurred. A massive toxic Pseudo-nitzschia bloom affected the entire west coast of North America during 2015-2016, and was linked to a 'warm blob' of ocean water. Other smaller toxic blooms occurred in the Gulf of Mexico and east coast of North America. Knowledge gaps remain, including how and why DA and its isomers are produced, the world distribution of potentially toxigenic Nitzschia species, the prevalence of DA isomers, and molecular markers to discriminate between toxigenic and non-toxigenic species and to discover sexually reproducing populations in the field.
During the months of January-February and May-June 2013 coinciding with the red tide occurrence in Kota Kinabalu, Sabah, Malaysia, six episodes involving 58 cases of paralytic shellfish poisoning (PSP) or saxitoxin (STX) poisoning and resulting in four deaths were reported. Many of them were intoxicated from consuming shellfish purchased from the markets, whereas others were intoxicated from eating shellfish collected from the beach. Levels of STX in shellfish collected from the affected areas were high (mean 2,920 ± 780 and 360 ± 140 µg STX equivalents/100 g shellfish meat respectively for the two periods). The count of toxic dinoflagellates (Pyrodinium bahamense var compressum) of the sea water sampled around the coast was also high (mean 34,200 ± 10,300 cells/L). Species of shellfish containing high levels of STX were Atrina fragilis, Perna viridis, and Crassostrea belcheri. The age of victims varied from 9 to 67 years. Symptoms presented were typical of PSP, such as dizziness, numbness, vomiting, and difficulty in breathing. Recommended steps to prevent or reduce PSP in future red tide season include better monitoring of red tide occurrence, regular sampling of shellfish for determination of STX level, wider dissemination of information on the danger of eating contaminated shellfish among the communities, fishermen, and fishmongers.
Numerous prevalence studies and outbreaks of Vibrio parahaemolyticus infection have been extensively reported in shellfish and crustaceans. Information on the quantitative detection of V. parahaemolyticus in finfish species is limited. In this study, short mackerels (Rastrelliger brachysoma) obtained from different retail marketplaces were monitored with the presence of total and pathogenic strains of V. parahaemolyticus. Out of 130 short mackerel samples, 116 (89.2%) were detected with the presence of total V. parahaemolyticus and microbial loads of total V. parahaemolyticus ranging from <3 to >10(5) MPN/g. Prevalence of total V. parahaemolyticus was found highest in wet markets (95.2%) followed by minimarkets (89.1%) and hypermarkets (83.3%). Pathogenic V. parahaemolyticus strains (tdh+ and/or trh+) were detected in 16.2% (21 of 130) of short mackerel samples. The density of tdh+ V. parahaemolyticus strains were examined ranging from 3.6 to >10(5) MPN/g and microbial loads of V. parahaemolyticus strains positive for both tdh and trh were found ranging from 300 to 740 MPN/g. On the other hand, antibiotic susceptibility profiles of V. parahaemolyticus strains isolated from short mackerels were determined through disc diffusion method in this study. Assessment of antimicrobial susceptibility profile of V. parahaemolyticus revealed majority of the isolates were highly susceptible to ampicillin sulbactam, meropenem, ceftazidime, and imipenem, but resistant to penicillin G and ampicillin. Two isolates (2.99%) exhibited the highest multiple antibiotic resistance (MAR) index value of 0.41 which shown resistance to 7 antibiotics. Results of the present study demonstrated that the occurrence of pathogenic V. parahaemolyticus strains in short mackerels and multidrug resistance of V. parahaemolyticus isolates could be a potential public health concerns to the consumer. Furthermore, prevalence data attained from the current study can be further used to develop a microbial risk assessment model to estimate health risks associated with the consumption of short mackerels contaminated with pathogenic V. parahaemolyticus.
Snail is one of the worst causes of food allergy. Thus, the aim of this study was to identify the major and minor allergens of the local marine snail (Cerithidea obtusa) and subsequently to investigate the impacts of heat treatment on the IgE-binding activity of snail allergens. Proteins from raw and heat-treated snails (boiled, roasted and fried) were extracted and then resolved by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Immunoblotting of all extracts were then performed using sera from patients with snail allergy. The results showed that the raw extract contains numerous protein bands between 12 to>250 kDa. Some thermostable proteins, predominantly the 33 and 42 kDa bands, remained detected in all cooked extracts with decreasing intensities from boiled to roasted to fried extracts, while the majority of thermolabile bands denatured after heating. Boiled snail had more protein bands compared to roasted and fried snails. Immunoblotting of raw extract demostrated 19 IgE-binding bands ranging from 15 to 240 kDa. The thermostable bands of 33 and 42 kDa and a thermolabile of 30 kDa band were identified as the major allergens of this snail. The cooked extracts yielded less allergenic bands. The boiled extract yielded approximately 14 IgE-binding bands with some smeared bands at high molecular weight regions. The roasted extract had lesser IgE-binding bands and the majority appeared as smears, while the IgE-reactivity in the fried extract was less visible and appeared as weak smears. This study indicated that both raw and cooked snails played a crucial role in snail allergenicity, as this species of snail contains both thermostable and thermolabile major allergens. The degree of snail allergenicity was revealed in the order: raw> boiled > roasted> fried. Thus, the results would facilitate in the development of effective diagnosis and management strategies of snail allergy in this country.
This study was undertaken to assess the levels of trace metals (As, Cd, Cu, Pb, and Zn) in two common species of cockles (Anadara granosa and Anadara inaequivalvis) from two coastal areas in Thailand (Pattani Bay) and Malaysia (the Setiu Wetlands). A total of 350 cockles were collected in February and September 2014. Trace metals were determined by Inductively Coupled Plasma Mass Spectrometry. We observed that cockles in both areas had a higher accumulation of metals in September. Notably, the biota-sediment accumulation (BSAF) of Cd was highest in both areas. A strong positive correlation of Cd with the length of the cockles at Pattani Bay (r(2) = 0.597) and the Setiu Wetlands (r(2) = 0.675) was noted. It was suggested that As could be a limiting element (BSAF < 1) of cockles obtained from Pattani Bay. In comparison with the permissible limits set by the Thailand Ministry of Public Health and the Malaysia Food Regulations, mean values of As, Cd, Cu, Pb, and Zn were within acceptable limits, but the maximum values of Cd and Pb exceeded the limits for both areas. Regular monitoring of trace metals in cockles from both areas is suggested for more definitive contamination determination.
Allergy diagnosis needs to be improved in polysensitized patients due to the existence of possible confounding factors in this type of patients. Component resolved diagnosis (CRD) is a new concept in the investigation of polysensitized patients. The aim of this study was to evaluate if the utilization of ImmunoCAP ISAC improve the diagnosis of the polysensitized allergic rhinitis patients. Skin prick test (SPT) to 58 crude allergen extracts and CRD (ImmunoCAP ISAC) were carried out for 5 polysensitized allergic rhinitis patients. Two patients had a shellfish allergy and avoidance of shellfish was the only way to prevent an allergic reaction. In contrast, although the remaining three patients had low risk for shellfish allergy, but they were the best candidates for immunotherapy using mite extracts. CRD and particularly ImmunoCAP ISAC have proven to be a valuable diagnostic tool in polysensitized patients. ImmunoCAP ISAC helps refine the individual patient's sensitization profile and predict the potential risk of allergic reactions and improve the selection of patients for immunotherapy.
The commercial freshwater crayfish Cherax quadricarinatus complete mitochondrial genome was recovered from partial genome sequencing using the MiSeq Personal Sequencer. The mitogenome has 15,869 base pairs consisting of 13 protein-coding genes, 2 ribosomal subunit genes, 22 transfer RNAs, and a non-coding AT-rich region. The base composition of C. quadricarinatus is 32.16% for T, 23.39% for C, 33.26% for A, and 11.19% for G, with an AT bias of 65.42%.
Vibrio parahaemolyticus is a main foodborne disease in seafood and generally seafood is
easily deteriorates in quality of color and flavor. In this study, clove (Syzygium aromaticum)
extract shows potent antibacterial activity against growth of antibiotics resistant Vibrio
parahaemolyticus on seafood samples (cockles and shrimps). Vibrio parahaemolyticus was
artificial contaminates on the samples with 106 CFU/ml. The samples were treated with different
concentration of cloves extract with 10 mg/ml which are 0.5%, 5% and 10% concentration
from methanol food grade extraction in 0 hr, 5 min, 10 min, 15 min, 30 min, 60 min and
120 min. Tab water and deionized water were selected as a negative control. As a result, the
amount of 10 % cloves managed to mitigates the number of V. parahaemolyticus on seafood
samples in 5 minutes and 15 min on both samples. Therefore, our results signify the fact that
cloves can be apply as natural sanitizer which could meet consumer demands for safe and
traditionally consumed either raw without any undesirable effect when applied in the seafood
system industries.