Chitosan is a biotechnological derivative of chitin receiving a widespread pharmaceutical and biomedical applications. It can be used to encapsulate and deliver cancer therapeutics with inherent pH-dependent solubility to confer drug targeting at tumour microenvironment and anti-cancer activity synergizing cancer cytotoxic drug actions. To further reduce the off-target and by-stander adverse effects of drugs, a high targeted drug delivery efficiency at the lowest possible drug doses is clinically required. The chitosan has been functionalized with covalent conjugates or complexes and processed into nanoparticles to encapsulate and control drug release, to avoid premature drug clearance, to deliver drugs passively and actively to cancer site at tissue, cell or subcellular levels, and to promote cancer cell uptake of nanoparticles through membrane permeabilization at higher specificity and scale. Nanomedicine developed using functionalized chitosan translates to significant preclinical improvements. Future challenges related to nanotoxicity, manufacturability, selection precision of conjugates and complexes as a function of cancer omics and their biological responses from administration site to cancer target need critical assessments.
In recent years, environmental problems caused by the use of fossil fuels and the depletion of petroleum reserves have driven the world to adopt biodiesel as an alternative energy source to replace conventional petroleum-derived fuels because of biodiesel's clean and renewable nature. Biodiesel is conventionally produced in homogeneous, heterogeneous, and enzymatic catalysed processes, as well as by supercritical technology. All of these processes have their own limitations, such as wastewater generation and high energy consumption. In this context, the membrane reactor appears to be the perfect candidate to produce biodiesel because of its ability to overcome the limitations encountered by conventional production methods. Thus, the aim of this paper is to review the production of biodiesel with a membrane reactor by examining the fundamental concepts of the membrane reactor, its operating principles and the combination of membrane and catalyst in the catalytic membrane. In addition, the potential of functionalised carbon nanotubes to serve as catalysts while being incorporated into the membrane for transesterification is discussed. Furthermore, this paper will also discuss the effects of process parameters for transesterification in a membrane reactor and the advantages offered by membrane reactors for biodiesel production. This discussion is followed by some limitations faced in membrane technology. Nevertheless, based on the findings presented in this review, it is clear that the membrane reactor has the potential to be a breakthrough technology for the biodiesel industry.
Chitin, as the main component of the exoskeleton of Arthropoda, is a highly available natural polymer that can be processed into various value-added products. Its most important derivative, i.e., chitosan, comprising β-1,4-linked 2-amino-2-deoxy-β-d-glucose (deacetylated d-glucosamine) and N-acetyl-d-glucosamine units, can be prepared via alkaline deacetylation process. Chitosan has been used as a biodegradable, biocompatible, non-antigenic, and nontoxic polymer in some in-vitro applications, but the recently found potentials of chitosan for in-vivo applications based on its biological activities, especially antimicrobial, antioxidant, and anticancer activities, have upgraded the chitosan roles in biomaterials. Chitosan approval, generally recognized as a safe compound by the United States Food and Drug Administration, has attracted much attention toward its possible applications in diverse fields, especially biomedicine and agriculture. Despite some favorable characteristics, the chitosan's structure should be customized for advanced applications, especially due to its drawbacks, such as low drug-load capacity, low solubility, high viscosity, lack of elastic properties, and pH sensitivity. In this context, derivatization with relatively inexpensive and highly available mono- and di-saccharides to soluble branched chitosan has been considered a "game changer". This review critically scrutinizes the emerging technologies based on the synthesis and application of lactose- and galactose-modified chitosan as two important chitosan derivatives. Some characteristics of chitosan derivatives and biological activities have been detailed first to understand the value of these natural polymers. Second, the saccharide modification of chitosan has been discussed briefly. Finally, the applications of lactose- and galactose-modified chitosan have been scrutinized and compared to native chitosan to provide an insight into the current state-of-the research for stimulating new ideas with the potential of filling research gaps.
The annual harvest of banana and plantain (Musa spp.) is approximately 145 million tons worldwide. About 85% of this global production comes from small plots and kitchen or backyard gardens from the developing world, and only 15% goes to the export trade. Musa acuminata and Musa balbisiana are the ancestors of several hundreds of parthenocarpic Musa diploid and polyploid cultivars, which show multiple origins through inter- and intra-specific hybridizations from these two wild diploid species. Generating hybrids combining host plant resistance to pathogens and pests, short growth cycles and height, high fruit yield, parthenocarpy, and desired quality from the cultivars remains a challenge for Musa crossbreeding, which started about one century ago in Trinidad. The success of Musa crossbreeding depends on the production of true hybrid seeds in a crop known for its high levels of female sterility, particularly among polyploid cultivars. All banana export cultivars grown today are, however, selections from somatic mutants of the group Cavendish and have a very narrow genetic base, while smallholders in sub-Saharan Africa, tropical Asia and Latin America use some bred-hybrids (mostly cooking types). Musa improvement goals need to shift to address emerging threats because of the changing climate. Innovative cell and molecular biology tools have the potential to enhance the pace and efficiency of genetic improvement in Musa. Micro-propagation has been successful for high throughput of clean planting materials while in vitro seed germination assists in obtaining seedlings after inter-specific and across ploidy hybridization. Flow cytometry protocols are used for checking ploidy among genebank accessions and breeding materials. DNA markers, the genetic maps based on them, and the recent sequencing of the banana genome offer means for gaining more insights in the genetics of the crops and to identifying genes that could lead to accelerating Musa betterment. Likewise, DNA fingerprinting has been useful to characterize Musa diversity. Genetic engineering provides a complementary tool to Musa breeders who can introduce today transgenes that may confer resistance to bacteria, fungi and nematodes, or enhance pro-vitamin A fruit content. In spite of recent advances, the genetic improvement of Musa depends on a few crossbreeding programs (based in Brazil, Cameroon, Côte d'Ivoire, Guadeloupe, Honduras, India, Nigeria, Tanzania and Uganda) or a handful of genetic engineering endeavors (Australia, Belgium, India, Kenya, Malaysia and Uganda). Development investors (namely international aid and philanthropy) should therefore increase their funding to genetically enhance this crop that ranks among the 10-top staple foods of the developing world.
Microalgae biorefinery is a platform for the conversion of microalgal biomass into a variety of value-added products, such as biofuels, bio-based chemicals, biomaterials, and bioactive substances. Commercialization and industrialization of microalgae biorefinery heavily rely on the capability and efficiency of large-scale cultivation of microalgae. Thus, there is an urgent need for novel technologies that can be used to monitor, automatically control, and precisely predict microalgae production. In light of this, innovative applications of the Internet of things (IoT) technologies in microalgae biorefinery have attracted tremendous research efforts. IoT has potential applications in a microalgae biorefinery for the automatic control of microalgae cultivation, monitoring and manipulation of microalgal cultivation parameters, optimization of microalgae productivity, identification of toxic algae species, screening of target microalgae species, classification of microalgae species, and viability detection of microalgal cells. In this critical review, cutting-edge IoT technologies that could be adopted to microalgae biorefinery in the upstream and downstream processing are described comprehensively. The current advances of the integration of IoT with microalgae biorefinery are presented. What this review discussed includes automation, sensors, lab-on-chip, and machine learning, which are the main constituent elements and advanced technologies of IoT. Specifically, future research directions are discussed with special emphasis on the development of sensors, the application of microfluidic technology, robotized microalgae, high-throughput platforms, deep learning, and other innovative techniques. This review could contribute greatly to the novelty and relevance in the field of IoT-based microalgae biorefinery to develop smarter, safer, cleaner, greener, and economically efficient techniques for exhaustive energy recovery during the biorefinery process.
Identification of microalgae species is of importance due to the uprising of harmful algae blooms affecting both the aquatic habitat and human health. Despite this occurence, microalgae have been identified as a green biomass and alternative source due to its promising bioactive compounds accumulation that play a significant role in many industrial applications. Recently, microalgae species identification has been conducted through DNA analysis and various microscopy techniques such as light, scanning electron, transmission electron, and atomic force -microscopy. The aforementioned procedures have encouraged researchers to consider alternate ways due to limitations such as costly validation, requiring skilled taxonomists, prolonged analysis, and low accuracy. This review highlights the potential innovations in digital microscopy with the incorporation of both hardware and software that can produce a reliable recognition, detection, enumeration, and real-time acquisition of microalgae species. Several steps such as image acquisition, processing, feature extraction, and selection are discussed, for the purpose of generating high image quality by removing unwanted artifacts and noise from the background. These steps of identification of microalgae species is performed by reliable image classification through machine learning as well as deep learning algorithms such as artificial neural networks, support vector machines, and convolutional neural networks. Overall, this review provides comprehensive insights into numerous possibilities of microalgae image identification, image pre-processing, and machine learning techniques to address the challenges in developing a robust digital classification tool for the future.
Surfactants have always been a prominent chemical that is useful in various sectors (e.g., cleaning agent production industry, textile industry and painting industry). This is due to the special ability of surfactants to reduce surface tension between two fluid surfaces (e.g., water and oil). However, the current society has long omitted the harmful effects of petroleum-based surfactants (e.g., health issues towards humans and reducing cleaning ability of water bodies) due to their usefulness in reducing surface tension. These harmful effects will significantly damage the environment and negatively affect human health. As such, there is an urgency to secure environmentally friendly alternatives such as glycolipids to reduce the effects of these synthetic surfactants. Glycolipids is a biomolecule that shares similar properties with surfactants that are naturally synthesized in the cell of living organisms, glycolipids are amphiphilic in nature and can form micelles when glycolipid molecules clump together, reducing surface tension between two surfaces as how a surfactant molecule is able to achieve. This review paper aims to provide a comprehensive study on the recent advances in bacteria cultivation for glycolipids production and current lab scale applications of glycolipids (e.g., medical and waste bioremediation). Studies have proven that glycolipids are effective anti-microbial agents, subsequently leading to an excellent anti-biofilm forming agent. Heavy metal and hydrocarbon contaminated soil can also be bioremediated via the use of glycolipids. The major hurdle in the commercialization of glycolipid production is that the cultivation stage and downstream extraction stage of the glycolipid production process induces a very high operating cost. This review provides several solutions to overcome this issue for glycolipid production for the commercialization of glycolipids (e.g., developing new cultivating and extraction techniques, using waste as cultivation medium for microbes and identifying new strains for glycolipid production). The contribution of this review aims to serve as a future guideline for researchers that are dealing with glycolipid biosurfactants by providing an in-depth review on the recent advances of glycolipid biosurfactants. By summarizing the points discussed as above, it is recommended that glycolipids can substitute synthetic surfactants as an environmentally friendly alternative.
Advanced fed-batch microbioreactors mitigate scale up risks and more closely mimic industrial cultivation practices. Recently, high throughput microscale feeding strategies have been developed which improve the accessibility of microscale fed-batch cultivation irrespective of experimental budget. This review explores such technologies and their role in accelerating bioprocess development. Diffusion- and enzyme-controlled feeding achieve a continuous supply of substrate while being simple and affordable. More complex feed profiles and greater process control require additional hardware. Automated liquid handling robots may be programmed to predefined feed profiles and have the sensitivity to respond to deviations in process parameters. Microfluidic technologies have been shown to facilitate both continuous and precise feeding. Holistic approaches, which integrate automated high-throughput fed-batch cultivation with strategic design of experiments and model-based optimisation, dramatically enhance process understanding whilst minimising experimental burden. The incorporation of real-time data for online optimisation of feed conditions can further refine screening. Although the technologies discussed in this review hold promise for efficient, low-risk bioprocess development, the expense and complexity of automated cultivation platforms limit their widespread application. Future attention should be directed towards the development of open-source software and reducing the exclusivity of hardware.
Biological removal of carbon, nitrogen and sulfur is drawing increasing research interest in search for an efficient and cost-effective wastewater treatment. While extensive work on separate removal of nitrogen and sulfur is well documented, investigation on simultaneous denitrifying sulfide removal has only been reported recently. Most of the work on denitrifying sulfide removal has been focusing on bioreactor performance, loading and operating conditions. Nonetheless, underlying principles elucidating the biochemical reactions and the mechanisms of the microbial degradation are yet to be established. In addition, unstable denitrifying sulfide removal which is a major operating problem that hinders practical application of the process, is yet to be resolved. This paper provides a review on the state-of-the-art development of simultaneous biological removal of sulfur, nitrogen and carbon. Research on bioreactor operation and performance, reactor configurations, mechanisms and modeling work including the use of mass balance analysis and artificial neural networks is delineated. An in-depth discussion on the microbial community and functional consortium is also provided. Challenges and future work on simultaneous biological removal of nitrogen-sulfur-carbon are also outlined.
In the last few years, biodiesel has emerged as one of the most potential renewable energy to replace current petrol-derived diesel. It is a renewable, biodegradable and non-toxic fuel which can be easily produced through transesterification reaction. However, current commercial usage of refined vegetable oils for biodiesel production is impractical and uneconomical due to high feedstock cost and priority as food resources. Low-grade oil, typically waste cooking oil can be a better alternative; however, the high free fatty acids (FFA) content in waste cooking oil has become the main drawback for this potential feedstock. Therefore, this review paper is aimed to give an overview on the current status of biodiesel production and the potential of waste cooking oil as an alternative feedstock. Advantages and limitations of using homogeneous, heterogeneous and enzymatic transesterification on oil with high FFA (mostly waste cooking oil) are discussed in detail. It was found that using heterogeneous acid catalyst and enzyme are the best option to produce biodiesel from oil with high FFA as compared to the current commercial homogeneous base-catalyzed process. However, these heterogeneous acid and enzyme catalyze system still suffers from serious mass transfer limitation problems and therefore are not favorable for industrial application. Nevertheless, towards the end of this review paper, a few latest technological developments that have the potential to overcome the mass transfer limitation problem such as oscillatory flow reactor (OFR), ultrasonication, microwave reactor and co-solvent are reviewed. With proper research focus and development, waste cooking oil can indeed become the next ideal feedstock for biodiesel.
Deep eutectic solvents (DESs) have been touted recently as potential alternatives to ionic liquids (ILs). Although they possess core characteristics that are similar to those of ILs (e.g., low volatility, non-flammability, low melting points, low vapor pressure, dipolar nature, chemical and thermal stability, high solubility, and tuneability), DESs are superior in terms of the availability of raw materials, the ease of storage and synthesis, and the low cost of their starting materials. As such, they have become the subject of intensive research in various sectors, notably the chemical, electrochemical, and biological sectors. To date, the applications of DESs have shown great promise, especially in the medical and biotechnological fields. In spite of these various achievements, the safety concern for these mixtures must be sufficiently addressed. Indeed, in order to exploit the vast array of opportunities that DESs offer to the biological industry, first, they must be established as safe mixtures. Hence, the biotechnological applications of DESs only can be implemented if they are proven to have negligible or low toxicity profiles. This review is the first of its kind, and it discusses two current aspects of DES-based research. First, it describes the properties of these mixtures with ample focus on their toxicity profiles. Second, it provides an overview of the breakthroughs that have occurred and the foreseeable prospects of the use of DESs in various biotechnological and biological applications.
The immune system is tasked to keep our body unharmed and healthy. In the immune system, B- and T-lymphocytes are the two main components working together to stop and eliminate invading threats like virus particles, bacteria, fungi and parasite from attacking our healthy cells. The function of antibodies is relatively more direct in target recognition as compared to T-cell receptors (TCR) which recognizes antigenic peptides being presented on the major histocompatibility complex (MHC). Although phage display has been widely applied for antibody presentation, this is the opposite in the case of TCR. The cell surface TCR is a relatively large and complex molecule, making presentation on phage surfaces challenging. Even so, recombinant versions and modifications have been introduced to allow the growing development of TCR in phage display. In addition, the increasing application of TCR for immunotherapy has made it an important binding motif to be developed by phage display. This review will emphasize on the application of phage display for TCR discovery as well as the engineering aspect of TCR for improved characteristics.
Culturing of microalgae as an alternative feedstock for biofuel production has received a lot of attention in recent years due to their fast growth rate and ability to accumulate high quantity of lipid and carbohydrate inside their cells for biodiesel and bioethanol production, respectively. In addition, this superior feedstock offers several environmental benefits, such as effective land utilization, CO(2) sequestration, self-purification if coupled with wastewater treatment and does not trigger food versus fuel feud. Despite having all these 'theoretical' advantages, review on problems and issues related to energy balance in microalgae biofuel are not clearly addressed until now. Base on the maturity of current technology, the true potential of microalgae biofuel towards energy security and its feasibility for commercialization are still questionable. Thus, this review is aimed to depict the practical problems that are facing the microalgae biofuel industry, covering upstream to downstream activities by accessing the latest research reports and critical data analysis. Apart from that, several interlink solutions to the problems will be suggested with the purpose to bring current microalgae biofuel research into a new dimension and consequently, to revolutionize the entire microalgae biofuel industry towards long-term sustainability.
Palm oil industry is one of the leading agricultural industries in Malaysia with average crude palm oil production of more than 13 million tonne per year. However, production of such huge amount of crude palm oil has consequently resulted to even larger amount of palm oil mill effluent (POME). POME is a highly polluting wastewater with high chemical oxygen demand (COD) and biochemical oxygen demand (BOD) in which can caused severe pollution to the environment, typically pollution to water resources. On the other hand, POME was identified as a potential source to generate renewable bioenergies such as biomethane and biohydrogen through anaerobic digestion. In other words, a combination of wastewater treatment and renewable bioenergies production would be an added advantage to the palm oil industry. In line with the world's focus on sustainability concept, such strategy should be implemented immediately to ensure palm oil is produced in an environmental friendly and sustainable manner. This review aims to discuss various technologies to convert POME to biomethane and biohydrogen in a commercial scale. Furthermore, discussion on using POME to culture microalgae for biodiesel and bioethanol production was included in the present paper as a new remedy to utilize POME with a greater beneficial return.
Microalgae have caught the world's attention for its potential to solve one of the world's most pressing issues-sustainable green energy. Compared to biofuels supplied by oil palm, rapeseed, soybean and sugar cane, microalgae alone can be manipulated to generate larger amounts of biodiesel, bioethanol, biohydrogen and biomass in a shorter time. Apart from higher productivity, microalgae can also grow using brackish water on non-arable land, greatly reducing the competition with food and cash crops. Hence, numerous efforts have been put into the commercialisation of microalgae-derived biofuel by both the government and private bodies. This paper serves to review conventional and novel methods for microalgae culture and biomass harvest, as well as recent developments in techniques for microalgal biofuel production.
Microalgae showcase an extraordinary capacity for synthesizing high-value phytochemicals (HVPCs), offering substantial potential for diverse applications across various industries. Emerging research suggests that subjecting microalgae to abiotic stress during cultivation and the harvesting stages can further enhance the accumulation of valuable metabolites within their cells, including carotenoids, antioxidants, and vitamins. This study delves into the pivotal impacts of manipulating abiotic stress on microalgae yields, with a particular focus on biomass and selected HVPCs that have received limited attention in the existing literature. Moreover, approaches to utilising abiotic stress to increase HVPCs production while minimising adverse effects on biomass productivity were discussed. The present study also encompasses a techno-economic assessment (TEA) aimed at pinpointing significant bottlenecks in the conversion of microalgae biomass into high-value products and evaluating the desirability of various conversion pathways. The TEA methodology serves as a valuable tool for both researchers and practitioners in the quest to identify sustainable strategies for transforming microalgae biomass into high-value products and goods. Overall, this comprehensive review sheds light on the pivotal role of abiotic stress in microalgae cultivation, promising insights that could lead to more efficient and sustainable approaches for HVPCs production.
Aptamers are single-stranded oligonucleotides that can be artificially generated by a method called Systematic evolution of ligands by exponential enrichment (SELEX). The generated aptamers have been assessed for high-performance sensing applications due to their appealing characteristics. With either aptamers alone or complementing with antibodies, several high sensitive and portable sensors have been demonstrated for use in 'point-of-care testing'. Due to their high suitability and flexibility, aptamers are conjugated with nanostructures and utilized in field applications. Moreover, aptamers are more amenable to chemical modifications, making them capable of utilization with most developed sensors. In this overview, we discuss novel, portable, and aptamer-based sensing strategies that are suitable for 'point-of-care testing'.
Thermophiles and hyperthermophiles are present in various regions of the Earth, including volcanic environments, hot springs, mud pots, fumaroles, geysers, coastal thermal springs, and even deep-sea hydrothermal vents. They are also found in man-made environments, such as heated compost facilities, reactors, and spray dryers. Thermophiles, hyperthermophiles, and their bioproducts facilitate various industrial, agricultural, and medicinal applications and offer potential solutions to environmental damages and the demand for biofuels. Intensified efforts to sequence the entire genome of hyperthermophiles and thermophiles are increasing rapidly, as evidenced by the fact that over 120 complete genome sequences of the hyperthermophiles Aquificae, Thermotogae, Crenarchaeota, and Euryarchaeota are now available. In this review, we summarise the major current applications of thermophiles and thermozymes. In addition, emphasis is placed on recent progress in understanding the biodiversity, genomes, transcriptomes, metagenomes, and single-cell sequencing of thermophiles in the genomic era.
The growing momentum of several common life-style diseases such as myocardial infarction, cardiovascular disorders, stroke, hypertension, diabetes, and atherosclerosis has become a serious global concern. Recent developments in the field of proteomics offering promising solutions to solving such health problems stimulates the uses of biopeptides as one of the therapeutic agents to alleviate disease-related risk factors. Functional peptides are typically produced from protein via enzymatic hydrolysis under in vitro or in vivo conditions using different kinds of proteolytic enzymes. An array of biological activities, including antioxidative, antihypertensive, antidiabetic and immunomodulating has been ascribed to different types of biopeptides derived from various food sources. In fact, biopeptides are nutritionally and functionally important for regulating some physiological functions in the body; however, these are yet to be extensively addressed with regard to their production through advance strategies, mechanisms of action and multiple biological functionalities. This review mainly focuses on recent biotechnological advances that are being made in the field of production in addition to covering the mode of action and biological activities, medicinal health functions and therapeutic applications of biopeptides. State-of-the-art strategies that can ameliorate the efficacy, bioavailability, and functionality of biopeptides along with their future prospects are likewise discussed.