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Microalgae metabolites include biologically active compounds with therapeutic effects such as anticancer, anti-inflammatory and immunomodulation effects. One of the most recent focuses is on utilizing microalgae lipid-based biologically active compounds in food applications. However, most microalgae biological active compounds in their natural forms have common drawbacks like low solubility, low physicochemical stability and strong susceptibility to degradation, which significantly limits their application in foods, therefore, it is important to find solutions to retain their functional properties. In the present work, a comprehensive review on multi-product biorefinery was carried out from upstream processing stage to downstream processing stage, and identify critical processes and factors that impact bioactive material acquisition and retention. Furthermore, since nanoencapsulation technology emerges as an effective solution for microalgae nutraceutical product's retention, this work also focus on the nanoparticle perspective and comprehensively reviews the current nanoencapsulation solutions of the microalgae bioactive extract products. The aim is to depict advances in the formulations of microalage bioactive nanoparticles and provide a critical analysis of the reported nanoparticle formation. Overall, through the investigation of microalgae from biomass to bioactive nanoparticles, we aim to facilitate microalgae nutraceuticals incorporation as high value-added ingredients in more functional food that can improve human health.

Microbial fermentation of organic matter under anaerobic conditions is currently the prominent pathway for biohydrogen production. Organic matter present in waste residues is regarded as an economic feedstock for biohydrogen production by dark and photo fermentative bacteria. Agricultural residues, fruit wastes, vegetable wastes, industrial wastewaters, and other livestock residues are some of the organic wastes most commonly used for biohydrogen production due to their higher organic content and biodegradability. Appropriate pretreatments are required to enhance the performance of biohydrogen from complex organic wastes. Biohydrogen production could also be enhanced by optimizing operation conditions and the addition of essential nutrients and nanoparticles. This review describes the pathways of biohydrogen production, discusses the effect of organic waste sources used and microbes involved on biohydrogen production, along with addressing the key parameters, advantages, and difficulties in each biohydrogen production pathway.

This study reports the isolation of a potential probiotic lactic acid bacteria (LAB) from fermented Solanum macrocarpon food and evaluates shrimp bacterial pathogens' inhibition. The isolate was determined by identifying the inhibition zone against Vibrio parahaemolyticus with an antagonistic activity of 360 AU/mL. Molecular identification based on 16S rRNA indicated that the isolate belongs to the Pediococcus genus, named as Pediococcus pentosaceus HN10. The isolate exhibited effective inhibitory ability against various pathogenic including antibiotic-resistant Vibrio spp., Escherichia coli ATCC 85922 and Staphylococcus aureus ATCC 25023. P. pentosaceus HN10 showed potential probiotic properties such as strong salt tolerance, low pH and bile salts resistance, autoaggregation and coaggregation activities. P. pentosaceus HN10 was negative for β-hemolytic and amino acid decarboxylase. Antibiotic resistance assay showed that this strain was sensitive to ampicillin and chloramphenicol. P. pentosaceus HN10 expressed strongly antioxidant activity. In vivo challenge to V. parahaemolyticus in shrimp model indicated P. pentosaceus HN10 enhanced survival rate, weight gain as well as reduced the number of Vibrio in shrimp intestine tract. Overall, this study suggests that P. pentosaceus HN10 could be applied as a supplementation feed for shrimp to minimize pathogenic bacteria's negative effect.

Fuel cells (FCs) are a chemical fuel device which can directly convert chemical energy into electrical energy, also known as electrochemical generator. Proton exchange membrane fuel cells (PEMFCs) are one of the most appealing FC systems that have been broadly developed in recent years. Due to the poor conductivity of electrolyte membrane used in traditional PEMFC, its operation at higher temperature is greatly limited. The incorporation of ionic liquids (ILs) which is widely regarded as a greener alternative compared to traditional solvents in the proton exchange membrane electrolyte shows great potential in high temperature PEMFCs (HT-PEMFCs). This review provides insights in the latest progress of utilizing ILs as an electrochemical electrolyte in PEMFCs. Besides, electrolyte membranes that are constructed by ILs combined with polybenzimidazole (PBI) have many benefits such as better thermal stability, improved mechanical properties, and higher proton conductivity. The current review aims to investigate the newest development and existing issues of ILs research in electrolyte and material selection, system fabrication method, synthesis of ILs, and experimental techniques. The evaluation of life cycle analysis, commercialization, and greenness of ILs are also discussed. Hence, this review provides insights to material scientists and develops interest of wider community, promoting the use of ILs to meet energy challenges.

This study investigates the effects of rice straw and potential nitrogen fixing Bacillus subtilis (Bacillus sp.) isolated from seafood wastewater on carbohydrate- and nitrogen mineralization from a long-term rice paddy soil by four weeks anaerobic incubation. Soil collected at the depth of 0–15 cm from a long-term rice paddy cultivation, and set up as following: (1) Control (10 g air dry soil), (2) Rice straw (control ＋ 0.2% rice straw w/v), (3) Bacillus sp., and (4) Combine (rice straw 0.2% w/v and Bacillus sp.) was subjected to an incubator in dark at room temperature/ submerge condition for 4 weeks anaerobic incubation. As showed in results, content of decomposed carbohydrate ranged from 83–447 mg kg −1 soil. Content of extracted carbohydrate was not affected by rice straw application, but significant decreased with bacillus or rice straw-bacillus combine inoculation (2.0–2.2 times decreased) compared to Control treatment, which is closely to the initial soil extraction carbohydrate. In contrary, mineralization nitrogen increased 120% in Bacillus sp. inoculation compared to Control treatment, but Rice straw and Combine treatments resulted in immobilization more than nitrogen mineralization. Inoculation of Bacillus subtilis is recommended as a good environment friendly method to enhance the soil fertility and reduce nitrogen immobilization. Further research within rice plant is therefore needed to consolidate the preliminary results.

The present research aims to study the long-term impacts of soil extractable carbohydrate content from the conversion of forest to paddy field, using three environmentally friendly methods: ultrasound assist (37 Hz/30 min), hot water (80 °C/4 h), and cold water (25 °C/30 min). Soil samples collected at the depth of 0–15 cm from natural forest, rice paddy, and border area were extracted by distilled water at the ratio 1:10 (soil: water). Contents of soil organic carbon (SOC) and extracted carbohydrate (ECH) in the natural forest and rice paddy were similar, and higher than in border area by 50%. Results showed the highest content of ECH was extracted using hot water (304–691 mg.Carbohydrate/kg soil, 4% of SOC), followed by ultrasound (102–305 mg.Carbohydrate/kg soil, 1.7% of SOC), and the lowest amount addressed to cold-water extraction (65–252 mg.Carbohydrate/kg soil, 1.2% of SOC). The ECH/SOC ratios in three soil types were the same and ranged from 0.9% to 4.2%. We conclude the long-term conversion of forest to rice paddy maintain both SOC and ECH, furthermore, hot water extraction at 80 °C/4 h is the optimum method for extraction of carbohydrate using non-chemical solvents.

Coronavirus Diseases 2019 (COVID-19) pandemic has a huge impact on the plastic waste management in many countries due to the sudden surge of medical waste which has led to a global waste management crisis. Improper management of plastic waste may lead to various negative impacts on the environment, animals, and human health. However, adopting proper waste management and the right technologies, looking in a different perception of the current crisis would be an opportunity. About 40% of the plastic waste ended up in landfill, 25% incinerated, 16% recycled and the remaining 19% are leaked into the environment. The increase of plastic wastes and demand of plastic markets serve as a good economic indicator for investor and government initiative to invest in technologies that converts plastic waste into value-added product such as fuel and construction materials. This will close the loop of the life cycle of plastic waste by achieving a sustainable circular economy. This review paper will provide insight of the state of plastic waste before and during the COVID-19 pandemic. The treatment pathway of plastic waste such as sterilisation technology, incineration, and alternative technologies available in converting plastic waste into value-added product were reviewed.

Spirulina biomass accounts for 30% of the total algae biomass production globally. In conventional process of Spirulina biomass production, cultivation using chemical-based culture medium contributes 35% of the total production cost. Moreover, the environmental impact of cultivation stage is the highest among all the production stages which resulted from the extensive usage of chemicals and nutrients. Thus, various types of culture medium such as chemical-based, modified, and alternative culture medium with highlights on wastewater medium is reviewed on the recent advances of culture media for Spirulina cultivation. Further study is needed in modifying or exploring alternative culture media utilising waste, wastewater, or by-products from industrial processes to ensure the sustainability of environment and nutrients source for cultivation in the long term. Moreover, the current development of utilising wastewater medium only support the growth of Spirulina however it cannot eliminate the negative impacts of wastewater. In fact, the recent developments in coupling with wastewater treatment technology can eradicate the negative impacts of wastewater while supporting the growth of Spirulina. The application of Spirulina cultivation in wastewater able to resolve the global environmental pollution issues, produce value added product and even generate green electricity. This would benefit the society, business, and environment in achieving a sustainable circular bioeconomy.

New pandemic infection of coronaviridae family virus spread to more than 210 countries with total infection of 1,136,851 and 62,955 (4.6%) deaths until 5th April 2020. Which stopped the regular cycle of humankind but the nature is consistently running. There is no micro molecule remedy found yet to restore the regular life of people. Hence, we decided to work on natural biophores against the COVID proteins. As a first step, major phytoconstituents of antiviral herbs like Leucas aspera, Morinda citrifolia, Azadirachta indica, Curcuma longa, Piper nigrum, Ocimum tenuiflorum, and Corallium rubrum collected and performed the lock and key analysis with major spike protein of COVID-19 to find the best fitting lead biophore using computational drug design platform. The results of protocol run showed, phytoconstituents of Morinda citrifolia and Leucas aspera were found lower binding energy range of - 55.18 to - 25.34 kcal/mol, respectively and compared with Hydroxychloroquine (HCQ) (- 24.29 kcal/mol) and Remdesivir (- 25.38 kcal/mol). The results conclude that, core skeletons chromen, anthracene 9, 11 dione and long-chain alkyl acids/ester-containing biophores showen high stable antagonistic affinity with S-protein. Which leads the breakdown of spike protein and ACE2 receptor complex formation and host mechanism of corono virus. In addition, the dynamic trajectory analysis confirmed the complete denaturation of spike protein by the molecule 4-(24-hydroxy-1-oxo-5-n-propyltetracosanyl)-phenol from Leucas aspera and stability of spike-ligand complex. These biophores will aid the researcher to fabricate new promising analogue and being recommended to assess its COVID-19 treatment.

Expired dairy products are often disposed of due to the potential health hazard they pose to living organisms. Lack of methods to recover valuable components from them are also a reason for manufactures to dispose of the expired dairy products. Milk encompasses several different components with their own functional properties that can be applied in production of food and non-food technical products. This study aims to investigate the novel approach of using liquid biphasic flotation (LBF) method for protein extraction from expired milk products and obtaining the optimal operating conditions for protein extraction. The optimized conditions were found at 80% concentration ethanol as top phase, 150 g/L dipotassium hydrogen phosphate along with 10% (w/v) milk as bottom phase, and a flotation time of 7.5 min. The protein recovery yield and separation efficiency after optimization were 94.97% and 86.289%, respectively. The experiment has been scaled up by 40 times to ensure it can be commercialized, and the protein recovery yield and separation efficiency were found to be 78.92% and 85.62%, respectively. This novel approach gives a chance for expired milk products to be changed from waste to raw materials which is beneficial for the environment and the economy.

The purpose of this investigation is to evaluate the implementation of ultrasound-assisted liquid biphasic flotation (LBF) system for the recovery of natural astaxanthin from Haematococcus pluvialis microalgae. Various operating conditions of ultrasound-assisted LBF systems such as the position of ultrasound horn, mode of ultrasonication (pulse and continuous), amplitude of ultrasonication, air flowrate, duration of air flotation, and mass of H. pluvialis microalgae were evaluated. The effect of ultrasonication on the cellular morphology of microalgae was also assessed using microscopic analysis. Under the optimized operating conditions of UALBF, the maximum recovery yield, extraction efficiency, and partition coefficient of astaxanthin were 95.08 ± 3.02%, 99.74 ± 0.05%, and 185.09 ± 4.78, respectively. In addition, the successful scale-up operation of ultrasound-assisted LBF system verified the practicability of this integrated approach for an effective extraction of natural astaxanthin.

This work aimed to study the application of liquid biphasic flotation (LBF) for the efficient and rapid recovery of astaxanthin from H. pluvialis microalgae. The performance of LBF for the extraction of astaxanthin was studied comprehensively under different operating conditions, including types and concentrations of food-grade alcohol and salt, volume ratio, addition of neutral salt, flotation period, and mass of dried H. pluvialis biomass powder. The maximum recovery, extraction efficiency and partition coefficient of astaxanthin obtained from the optimum LBF system were 95.11 ± 1.35%, 99.84 ± 0.05% and 385.16 ± 3.87, respectively. A scaled-up LBF system was also performed, demonstrating the feasibility of extracting natural astaxanthin from microalgae at a larger scale. This exploration of LBF system opens a promising avenue to the extraction of astaxanthin at lower cost and shorter processing time.

The microalgal-bacterial co-cultivation was adopted as an alternative in making microbial-based biofuel production to be more feasible in considering the economic and environmental prospects. Accordingly, the microalgal-bacterial symbiotic relationship was exploited to enhance the microbial biomass yield, while bioremediating the nitrogen-rich municipal wastewater. An optimized inoculation ratio of microalgae and activated sludge (AS:MA) was predetermined and further optimization was performed in terms of different increment ratios to enhance the bioremediation process. The nitrogen removal was found accelerating with the increase of the increment ratios of inoculated AS:MA, though all the increment ratios had recorded a near complete total nitrogen removal (94–95%). In light of treatment efficiency and lipid production, the increment ratio of 0.5 was hailed as the best microbial population size in accounting the total nitrogen removal efficiency of 94.45%, while not compromising the lipid production of 0.241 g/L. Moreover, the cultures in municipal wastewater had attained higher biomass and lipid productions of 1.42 g/L and 0.242 g/L, respectively, as compared with the synthetic wastewater which were only 1.12 g/L (biomass yield) and 0.175 g/L (lipid yield). This was possibly due to the presence of trace elements which had contributed to the increase of biomass yield; thus, higher lipid attainability from the microalgal-bacterial culture. This synergistic microalgal-bacterial approach had been proven to be effective in treating wastewater, while also producing useful biomass for eventual lipid production with comparable net energy ratio (NER) value of 0.27, obtained from the life-cycle analysis (LCA) studies. Thereby, contributing towards long-term sustainability and possible commercialization of microbial-based biofuel production.

The search of new sustainable energy sources based on renewable biomass feedstocks from lignocellulose biomass constituents namely cellulose, hemicellulose and lignin is a global effort to replace fossil fuel sources. Several conventional methods that have been used for extracting constituents via biomass dissolution include acid and base hydrolyses. However, these processes offer several drawbacks and therefore cannot be considered as environmental-friendly. This study investigates the dissolution of bamboo biomass from species Gigantochloa scortechini in low-viscosity ether-functionalized ionic liquids (ILs) by employing direct probe sonication method. Two ether-functionalized ILs which are MOE-MImCl and MOE-BImCl have been synthesized and characterized and their performance towards biomass dissolution have been tested. Results show that both MOE-MImCl and MOE-BImCl are able to dissolve the biomass with percentage dissolution of 88.1% and 28.1%, respectively with 20 minutes dissolution time. FTIR analyses were also done on both untreated biomass and regenerated biomass. The recyclability of the ILs for dissolving biomass was also tested and results show that the percentage of biomass dissolved in the recycled ILs reduce by approximately 10% of the original values.

Haematococcus pluvialis (H. pluvialis) microalgae are well known for their high content of astaxanthin, which is a super potent antioxidant with various remedial effects. Ionic liquids (ILs) have been proposed as a promising solvent to permeabilize the robust microalgal cell wall for an effective extraction of bioactive compounds. Nonetheless, the removal of ILs from the extracted compounds requires the additional treatment steps that complicate the overall extraction process and the recycling of ILs. To address these shortcomings, we demonstrated a sustainable extraction system that utilizes CO2-based alkyl carbamate ILs to permeate H. pluvialis cells and extract astaxanthin. This class of ILs is readily distillable for an easy recovery of ILs from the extraction medium. Among the tested CO2-based alkyl carbamate ILs [dimethylammonium dimethylcarbamate (DIMCARB), dipropylammonium dipropylcarbamate (DPCARB), dibutylammonium dibutylcarbamate (DBCARB) and diallyammonium diallycarbamate (DACARB)], DIMCARB gave the best performance of astaxanthin extraction. The optimized extraction conditions [100% (w/w) of DIMCARB, 75 min and 45 °C] resulted in the high yield of astaxanthin (27.99 mg/g). The capability of DIMCARB to permeabilize the amorphous trilayered structure of cell wall was verified by the presence of pores on the cell surface of H. pluvialis as shown in the microscope images. The performance and recyclability of DIMCARB extraction system were also evaluated by conducting three successive rounds of astaxanthin extraction with the recycled DIMCARB solutions. In addition, the antioxidant capacity of the extracted astaxanthin was well retained, showing that this type of distillable IL was suitable for the extraction of phytonutrients from algal source.

With the rapid urbanisation happening around the world followed by the massive demand for clean energy resources, green cities play a pivotal role in building a sustainable future for the people. The continuing depletion of natural resources has led to the development of renewable energy with algae as the promising source. The high growth rate of microalgae and their strong bio-fixation ability to convert CO2 into O2 have been gaining attention globally and intensive research has been conducted regarding the microalgae benefits. The focus on potential of microalgae in contributing to the development of green cities is rising. The advantage of microalgae is their ability to gather energy from sunlight and carbon dioxide, followed by transforming the nutrients into biomass and oxygen. This leads to the creation of green cities through algae cultivation as waste and renewable materials can be put to good use. The challenges that arise when using algae and the future prospect in terms of SDGs and economy will also be covered in this review. The future of green cities can be enhanced with the adaptation of algae as the source of renewable plants to create a better outlook of an algae green city.

Recent major studies have highlighted a newly discovered paradigm termed the “excludon”, which are overlapping transcripts that produce anticorrelated protein expression. These antisense overlapping transcripts are believed to act as common regulatory mechanisms in prokaryotes. Current research prevalence of excludons has only been demonstrated in Gram-positive bacteria and has not been explored in any Gram-negative or archaeal prokaryotes. To overcome this limitation, it is important to determine the frequency of excludons across all prokaryote domains in order to confirm its regulatory role in prokaryotes. With the recent advances in next-generation sequencing, it is now possible to define nucleic acid populations at an unprecedented depth and resolution. This study involves the evaluation of bioinformatics as a novel method to identify potential excludons and to investigate the occurrence of excludons in both bacterial (Gram-positive and Gram-negative) and archaeal strains. The paradigm of the excludons is mathematically represented using the Heaviside function to facilitate the identification of excludons with the help of computational algorithms. Based on the results, these excludons are likely to be common in both bacteria and archaea and may be a common regulatory system in prokaryotes.

Ionic liquids (ILs) have emerged as an alternative solvent used in the bioprocessing of microalgae for recovery of valuable biomolecules. The aim of this work is to extract fucoxanthin from Chaetoceros calcitrants (C. calcitrans) by using the readily distillable CO2-based alkyl carbamate ILs. The degree of cell permeabilization was analysed by the quantification of extracted fucoxanthin and the analyses of cell surface morphology. Among the tested CO2-based alkyl carbamate ILs, diallylammonium diallylcarbamate (DACARB) extraction system gave the maximal yield of fucoxanthin at 17.51 mg/g under the optimal extraction conditions [90% (v/v), 3 min and 25 °C]. Moreover, the extracted fucoxanthin fraction exhibited the satisfactory antioxidant activities. The recyclability of DACARB was demonstrated in the multiple batches of fucoxanthin extraction. Hence, CO2-based alkyl carbamate ILs can prospectively substitute conventional organic solvents in the downstream processing of bioactive compounds from microalgae.

Ionic liquid (IL) has been an attractive candidate for various industrial applications, especially in cellulose processing industry. The concerns over hazards of conventional volatile organic solvents can be overcome by ILs due to their unique and ‘green’ characteristics. However, the controversy over the usage of ILs in various fields remains on their toxicity toward living organisms and their environmental impact. This review intends to reveal the connection between sustainability of IL technology and the applications of IL in dissolution of lignocellulosic biomass as well as permeabilization of microalgae cells. The mechanism studies are comprehensively evaluated, and the molecular physicochemical aspects of ILs used in these cellulose-degrading processes are systematically presented. In addition, the techno-economic and sustainability analyses of these IL-based applications are compiled. The highlights in future prospect and challenges of adopting IL in these processes could align the future research effort to fill in the knowledge gaps. This review aims to deliver a different perspective on the consideration of “toxic” and “green” elements of IL used in biomass processing.

Chlorella sorokiniana is an alternative microalgal source of lutein, which is a type of phytonutrient with various health benefits. Different solvent extraction strategies have been explored for the recovery of carotenoids from microalgae. In particular, the conventional imidazolium- and pyridinium-based ionic liquids (ILs) are attractive due to their ability to permeabilize the microalgae. However, the challenges remain in separating the extracted carotenoid from ILs solvent. To overcome this shortcoming, CO2-based alkyl carbamate ILs were proposed as an alternative solvent that can function as a cell permeabilizing agent and an extraction solvent for recovery of lutein from Chlorella sorokiniana. A complete separation of lutein from the ILs was achievable by distillation of ILs under mild conditions. In an optimized extraction system conducted at room temperature for 45 min, a co-solvent system made of dipropylammonium dipropylcarbamate (DPCARB, 80% v/v) and methanol yielded 971.18 ± 17.88 mg/g lutein. The recyclability of DPCARB was tested and the results showed that the extraction performance of the recycled IL was satisfactory after three cycles of extraction. CO2-based alkyl carbamate ILs hold a good potential in the extraction of lutein due to their recyclability that mitigates environmental impact and reduces operating cost.

There has been increasing attention in osmotically driven membrane processes (ODMPs), which include forward osmosis (FO) and pressure retarded osmosis (PRO). They provide a sustainable solution against water and energy scarcity issues by utilizing the osmotic pressure difference between two water bodies, feed (low salinity) and draw solution (high salinity), across a semipermeable membrane. Indeed, their main applications, water treatment (e.g., desalination and wastewater treatment) and power generation, facilitate resource recovery from wastewaters. This review updates the recent development of FO and PRO by providing a comprehensive review on their fundamentals, membrane properties, potential applications as well as advanced techniques. In addition, economic analysis and environmental impacts are critically reviewed to highlight their feasibility and sustainability. Resource recovery from wastewaters (e.g., water, nutrient and energy) using FO and PRO is also discussed followed by their commercialization and future trends in order to push forward laboratory research to full-scale commercialization.

Microalgae has been utilised in various applications ranging from pharmaceuticals, cosmetics, supplements, liquid fuels as well as food source for human and animals. The upscaling of microalgae production to meet the demand for global consumption has yet to be realized as there are many factors to be considered in the upstream and downstream processing of microalgae biomass. For upstream processing, the high cultivation cost which poses a major setback can be reduced by cultivating the microalgae in wastewater sources, which are widely available and at the same time can lead to bioremediation of these waste sources. The contents of microalgae biomass from wastewater can also be used to produce the desired bioproducts. For downstream processing, the efficiency of traditional processes has long hindered the progression of microalgae to products, hence, the discovery of advanced technologies which can yield higher productivity and good quality products have been studied and upscale to a pilot scale to verify its feasibility. Separation techniques like liquid biphasic system and membrane separation are potential in achieving high yield and separation efficiency to recover valuable products from microalgae and these processes are environmentally friendly and cost-effective. The insights from cultivating microalgae in wastewater sources and the promising technologies to convert them into useful bioproducts will be beneficial to the developments of future upstream and downstream processes.

This study demonstrated a novel approach of lipids extraction with simultaneous biofuels conversion on microalgae Chlorella sorokiniana CY-1 cultivation using waste molasses as culture medium. The lipid extraction process was based on a hybrid liquid biphasic system (HLBS) which comprises of disruptive and extractive solvents in a single system. The microalgae cultivation with waste molasses showed a reduction in the chemical oxygen demand (COD), total suspended solid (TSS) and nitrate content on the waste medium (61.48 %, 63.94 % and 63.79 %, respectively). Additionally, a prompt lipids extraction with a recovery of 92.84 % and a cell disruption enhancement of 8.3-fold in the organic solvent phase was attained. The acid-treated C. sorokiniana CY-1 biomass showed a composition of carbon at 61.3 %, oxygen at 33.2 %, nitrogen at 5.5 % and potassium at 0.12 %. Sulphur content was not detected in the microalgae biomass and this had aided the production of fatty acids methyl ester (FAME) which was observed by a gas chromatographic-flame ionisation detector (GC-FID) profile. A disruptive-extraction method using acid assisted phase on HLBS showed potential for direct conversion of lipids into FAME to produce biofuels for engine combustion.

The increased global demand for plastic materials has led to severe plastic waste pollution, particularly to the marine environment. This critical issue affects both sea life and human beings since microplastics can enter the food chain and cause several health impacts. Plastic recycling, chemical treatments, incineration and landfill are apparently not the optimum solutions for reducing plastic pollution. Hence, this review presents two newly identified environmentally friendly approaches, plastic biodegradation and bioplastic production using algae, to solve the increased global plastic waste. Algae, particularly microalgae, can degrade the plastic materials through the toxins systems or enzymes synthesized by microalgae itself while using the plastic polymers as carbon sources. Utilizing algae for plastic biodegradation has been critically reviewed in this paper to demonstrate the mechanism and how microplastics affect the algae. On the other hand, algae-derived bioplastics have identical properties and characteristics as petroleum-based plastics, while remarkably being biodegradable in nature. This review provides new insights into different methods of producing algae-based bioplastics (e.g., blending with other materials and genetic engineering), followed by the discussion on the challenges and further research direction to increase their commercial feasibility.

In this study, we reported a laccase producing fungus from hard wood samples. The isolation produced laccase as extracellular enzymes under liquid culture using rice straw and wood chips as carbon sources. The enzyme accumulated highest activity after 12 days and 6 days cultivation on rice straw and wood chips, reaching 186 U/mL and 2.5 U/mL, respectively. Fe2＋ inhibited activity whereas Co2＋, Cu 2 + , and Mg 2 + significantly enhanced its activity. The optimal pH and temperature were 5.0 and 45°C, respectively. Molecular identification indicated that the isolation belonged in Fusarium genus and named as Fusairum oxysporum HUIB02. On the other hand, F. oxysporum HUIB02 showed excellent synthetic dyes decolouration for bromothymol blue, methyl orange, remazol brilliant blue R, indigo carmine with degree approximately 100%. The strain also exhibited great decolouration on malachite green and evans blue. These synthetic dyes enhanced laccase accumulation up to 12.6-fold in compared with culture in rice straw medium. SDS-PAGE zymogram analysis indicated F. oxysporum HUIB02 secreted two main laccases with molecular weight of 110 kDa (Lacc110) and 42 kDa (Lacc42). Laccase gene expression was affected by synthetic dyes. The Lacc110 expression level was suppressed whereas the Lacc42 expression level was induced. The results remarked F. oxysporum HUIB02 is a good source in laccase production and dye decolouration as well as synthetic dyes are directly affected on gene expression pathway in organism.

The world energy system faces two major challenges: the requirement for more energy and less carbon. It is important to address biofuels production as an alternative to the usage of fossil fuel by utilizing microalgae as the potential feedstock. Yet, the commercialization of microalgae remains contentious caused by factors relating to the life cycle assessment and feasibility of microalgae-based biofuels. This present review starts with an introduction to the benefits of microalgae, followed by intensive elaboration on microalgae cultivation parameters. Subsequently, the fundamental principle along with the advantages and disadvantages of various pretreatment techniques of microalgae were reviewed. In addition, the conventional and recent advances in lipid extraction techniques from microalgae were comprehensively evaluated. Comparative analysis regard to the gaps from previous studies was discussed point-by-point in each section. The effort presented in this review will provide an insight for future researches dealing with microalgae-biofuel production on downstream processing.

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The world energy production trumped by the exhaustive utilization of fossil fuels has highlighted the importance of searching for an alternative energy source that exhibits great potential. Ongoing efforts are being implemented to resolve the challenges regarding the preliminary processes before conversion to bioenergy such as pretreatment, enzymatic hydrolysis and cultivation of biomass. Nanotechnology has the ability to overcome the challenges associated with these biomass sources through their distinctive active sites for various reactions and processes. In this review, the potential of nanotechnology incorporated into these biomasses as an aid or addictive to enhance the efficiency of bioenergy generation has been reviewed. The fundamentals of nanomaterials along with their various bioenergy applications were discussed in-depth. Moreover, the optimization and enhancement of bioenergy production from lignocellulose, microalgae and wastewater using nanomaterials are comprehensively evaluated. The distinctive features of these nanomaterials contributing to better performance of biofuels, biodiesel, enzymes and microbial fuel cells are also critically reviewed. Subsequently, future trends and research needs are highlighted based on the current literature.

A well-known bioseparation technique namely liquid biphasic system (LBS) has attracted many researchers’ interest for being an alternative bioseparation technology for various kinds of biomolecules. The present review begins with an in-depth discussion on the fundamental principle of LBS and this is followed by the discussion on further development of various phase-forming components in LBS. Additionally, the implementation of various advance technologies to the LBS that is beneficial towards the efficiency of LBS for the extraction, separation, and purification of biomolecules was discussed. The key parameters affecting the LBS were presented and evaluated. Moreover, future prospect and challenges were highlighted to be a useful guide for future development of LBS. The efforts presented in this review will provide an insight for future researches in liquid-liquid separation techniques.

Forward osmosis (FO) and pressure-retarded osmosis (PRO) have gained attention recently as potential processes to solve water and energy scarcity problems with advantages over pressure-driven membrane processes. These processes can be designed to produce bioenergy and clean water at the same time (i.e., wastewater treatment with power generation). Despite having significant technological advancement, these bioenergy processes are yet to be implemented in full scale and commercialized due to its relatively low performance. Hence, massive and extensive research has been carried out to evaluate the variables in FO and PRO processes such as osmotic membrane, feed solutions, draw solutions, and operating conditions in order to maximize the outcomes, which include water flux and power density. However, these research findings have not been summarized and properly reviewed. The key parts of this review are to discuss the factors influencing the performance of FO and PRO with respective resulting effects and to determine the research gaps in their optimization with the aim of further improving these bioenergy processes and commercializing them in various industrial applications.

Haematococcus pluvialis is one of the most abundant sources of natural astaxanthin as compared to others microorganism. Therefore, it is important to understand the biorefinery of astaxanthin from H. pluvialis, starting from the cultivation stage to the downstream processing of astaxanthin. The present review begins with an introduction of cellular morphologies and life cycle of H. pluvialis from green vegetative motile stage to red non-motile haematocyst stage. Subsequently, the conventional biorefinery methods (e.g., mechanical disruption, solvent extraction, direct extraction using vegetable oils, and enhanced solvent extraction) and recent advanced biorefinery techniques (e.g., supercritical CO2 extraction, magnetic-assisted extraction, ionic liquids extraction, and supramolecular solvent extraction) were presented and evaluated. Moreover, future prospect and challenges were highlighted to provide a useful guide for future development of biorefinery of astaxanthin from H. pluvialis. The review aims to serve as a present knowledge for researchers dealing with the bioproduction of astaxanthin from H. pluvialis.