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The use of electrolyzed water as a green solution for managing Fusarium sp. causing agent rhizome to rot in turmeric has the potential for significant biorefinery applications. By using electrolyzed water to inhibit fungal growth, the remaining turmeric rhizomes can be converted into value-added products through various biorefinery processes, contributing to the sustainability of turmeric cultivation. Microbial contamination is the most significant obstacle that must be overcome after harvesting Zingiberaceae. Fusarium oxysporum had been reported to cause rhizome rot in turmeric. This experiment aimed to evaluate how alkaline electrolyzed water (AlEW) and acidic electrolyzed water (AcEW) affected the ability of Fusarium sp. to proliferate. A solution of NaCl at a concentration of 5% was electrolyzed to produce the electrolyzed water. The spore suspensions were exposed to AcEW for 5 and 10 min at different free chlorine concentrations of 0 (distilled water), 100, 200, 300, and 400 mg/L. Additionally, the spore suspensions were exposed to AlEW for 5 and 10 min at NaOH concentrations of 0 (distilled water), 125, 250, 500, and 750 mg/L. The spores were then spread out on potato dextrose agar (PDA) and cultured for 48 h at room temperature (28±2 °C) after the treatments. Then, using scanning electron microscopy (SEM), morphological damage to mycelial cells was observed. According to the findings, a 5 and 10 min exposure to AcEW at 100 mg/L led to the inhibition of Fusarium sp. growth, whereas, in contrast to the control group, rising AcEW concentrations at 200–400 mg/L led to total inhibition. The second experimental group treated the spore suspensions with AlEW at NaOH concentrations of 0 (distilled water), 125, 250, 500, and 750 mg/L for 5 and 10 min. Mycelial growth suppression was seen after treating AlEW for 5 min at 500 mg/L and 10 min at 250 mg/L. In addition, AlEW at 500 and 700 mg/L obtained the complete inhibition of Fusarium sp. SEM observation revealed that both AcEW and AlEW caused harm to the cell structure at all concentrations tested, as evidenced by the abnormal appearance of mycelial cells under microscopic examination. Hence, the electrolyzed water has the potential to reduce fungal growth during postharvest storage. [ABSTRACT FROM AUTHOR]

Aquaculture is vital for feeding a growing population as aquatic creatures require more protein. Utilizing protein-rich biomass for feeding animals is a possible solution. Biorefinery technology can extract protein and non-protein components from biomass, creating an economically feasible value chain. This study replaced fish feed with napier grass and used a compensatory response to reduce the cost of feeding Nile tilapia. The trial involved dividing mono-sex male Nile tilapia, initially weighing between 11.10 and 13.60 g/f, into four groups with three replications based on their feeding regime. Therefore, in the study, four groups of Nile tilapia were fed different diets for 90 days. The control group (T1) received a commercial floating pellet diet throughout the trial. Group T2 and T3 received a mix of commercial floating pellet diet and napier grass in varying proportions, and group T4 was fed with only napier grass throughout the trial. The study found that groups T2 and T3 had remarkable fish growth performance, high digestibility of napier grass, and lower feed prices with the highest benefit-cost ratios. The percentage of edible flesh and Hepatosomatic Index (PT2) were higher in group T2 than T3. Cellulase activity decreased with the frequency of napier grass intake, and the amylase activity was higher in T2 than T3, which also had the highest growth performance and feed utilization. Therefore, the study suggests that the optimal feeding regimen for Nile tilapia is T2 or T3, which promotes growth and is cost-effective. [ABSTRACT FROM AUTHOR]

Apart from protecting the environment from undesired waste impacts, wastewater treatment is a crucial platform for recovery. The exploitation of suitable technology to transform the wastes from pulp and paper industries (PPI) to value-added products is vital from an environmental and socio-economic point of view that will impact everyday life. As the volume and complexity of wastewater increase in a rapidly urbanizing world, the challenge of maintaining efficient wastewater treatment in a cost-effective and environmentally friendly manner must be met. In addition to producing treated water, the wastewater treatment plant (WWTP) has a large amount of paper mill sludge (PMS) daily. Sludge management and disposal are significant problems associated with wastewater treatment plants. Applying the biorefinery concept is necessary for PPI from an environmental point of view and because of the piles of valuables contained therein in the form of waste. This will provide a renewable source for producing valuables and bio-energy and aid in making the overall process more economical and environmentally sustainable. Therefore, it is compulsory to continue inquiry on different applications of wastes, with proper justification of the environmental and economic factors. This review discusses current trends and challenges in wastewater management and the bio-valorization of paper mills. Lignin has been highlighted as a critical component for generating valuables, and its recovery prospects from solid and liquid PPI waste have been suggested. [ABSTRACT FROM AUTHOR]

Third-generation biofuels from microalgae are becoming necessary for sustainable energy. In this context, this study explores the hydrothermal liquefaction (HTL) of microalgae biomass grown in wastewater, consisting of 30% Chlorella vulgaris , 69% Tetradesmus obliquus , and 1% cyanobacteria Limnothrix planctonica , and the subsequent upgrading of the produced bio-oil. The novelty of the work lies in integrating microalgae cultivation in wastewater with HTL in a biorefinery approach, enhanced using a catalyst to upgrade the bio-oil. Different temperatures (300, 325, and 350 °C) and reaction times (15, 30, and 45 min) were tested. The bio-oil upgrading occurred with a Cobalt-Molybdenum (CoMo) catalyst for 1 h at 375 °C. Post-HTL, although the hydrogen-to-carbon (H/C) ratio decreased from 1.70 to 1.38–1.60, the oxygen-to-carbon (O/C) ratio also decreased from 0.39 to 0.079–0.104, and the higher heating value increased from 20.6 to 36.4–38.3 MJ kg−1. Palmitic acid was the main component in all bio-oil samples. The highest bio-oil yield was at 300 °C for 30 min (23.4%). Upgrading increased long-chain hydrocarbons like heptadecane (5%), indicating biofuel potential, though nitrogenous compounds such as hexadecanenitrile suggest a need for further hydrodenitrogenation. Aqueous phase, solid residues, and gas from HTL can be used for applications such as biomass cultivation, bio-hydrogen, valuable chemicals, and materials like carbon composites and cement additives, promoting a circular economy. The study underscores the potential of microalgae-derived bio-oil as sustainable biofuel, although further refinement is needed to meet current fuel standards. [Display omitted] • HTL of wastewater-grown microalgae yields bio-oil with HHV up to 38.3 MJ kg−1. • Highest bio-oil yield (23.4%) at 300 °C for 15 min. • Nitrogenous compounds removal is still needed. • Upgraded bio-oil contains heptadecane (5%), indicating fuel potential. • Solid residues, gas, and aqueous phase reuse promotes circular economy. [ABSTRACT FROM AUTHOR]

In this study, an attempt was made to investigate bioethanol production using low-cost feedstock, namely, tobacco wastes obtained after the leaves harvesting. Tobacco stalks, an abundant biomass source of the leftover agricultural crop field, are a promising feedstock for bioethanol production. Traditional Thai tobacco (Nicotiana tabacum L.) is known as non-Virginia type tobacco stalks and was used as biomass feedstock for ethanol production by separate hydrolysis and fermentation (SHF) with a computerized fermenter. Tobacco stalks were efficiently hydrolyzed after a mild physical-chemical pretreatment. The economically cheapest alkaline chemical (2% CaO) was used for pretreatment. The robust yeast Saccharomyces cerevisiae was utilized, and it is suitable for industrial ethanol production. These data suggest that tobacco stalks are potential candidates for ethanol production from physical alkali-pretreated biomass with enzymatic hydrolysis on the SHF system. [ABSTRACT FROM AUTHOR]

Flavonoids are the secondary metabolites synthesized by microalgae and have diverse applications in various fields. The present study compares among two microalgal strains, Chlorella vulgaris (CV) and Chlorella pyrenoidosa (CP), for the production of flavonoids and lipids, which were cultivated in mixotrophic as well as autotrophic modes. This study also focuses on the role of l-phenylalanine as a supplement to enhance flavonoids. The current work establishes the relation between nitrates, external carbon, and l-phenylalanine for enhanced production of flavonoids and lipids. The extracted flavonoids were found to be maximum in CP-autotrophic mode followed by CV-mixotrophic mode with 138 μg/ml and 118 μg/ml, respectively. The common flavonoids observed with both the microalgal strains were quercetin, catechin, and p-coumaric acid. In comparison, the production of the maximum lipid of 23.7% was reported with mixotrophic operation in CV, followed by CP (19.4%). The scavenging activity of the extracted flavonoids was determined using a hydrogen peroxide assay and was found to be in the range of 63–73% at all experimental conditions. CP was found to produce more flavonoids in autotrophic mode, whereas mixotrophic mode showed maximum production of lipids and flavonoids in the CV. The simultaneous production of high value-added products, viz., flavonoids and lipids, not only paves a pathway for the biorefinery approach but also elevates the commercial potential during scale-up. Graphical abstract [ABSTRACT FROM AUTHOR]

Industrial production of fuels, commodity chemicals and value added products mainly depends on fossil resources. The demand for fossil derived fuels and chemicals has increased adding more concerns on climate change, global economic stability and sustainable supply of fossil resources. Therefore, lignocellulosic biomass (LCB) is receiving great attention as an alternative to fossil resources since it is globally available and sustainable feedstock. LCB is a sugar rich platform that can be converted to biofuels and specialty products through appropriate processing. Various conversion technologies are available for the production of fuels and value added products from LCB. However, sustainable biomass processing is still a global challenge requiring fulfillment of fundamental demands such as economic efficiency, environmental compatibility and societal responsibility. The key challenges being faced in biomass conversion include sustainable biomass supply, cost effective pretreatment technologies to make LCB amenable to efficient hydrolysis using less enzyme doses, development of low cost and efficient enzyme cocktails, conversion of all available sugars in LCB to fuels and value added products. The conversion of LCB to ethanol is complex and expensive and hence the cost of LCB derived ethanol cannot compete with fossil fuels. The promising strategy for low cost LCB derived ethanol production is to employ a biorefinery approach which integrates all the processes including physical, chemical and biological to produce bulk as well as high value chemicals from all the components of LCB. This review discusses on the latest developments in 2G-ethanol process and the integration of processes for some of the commodity as well as high value chemicals to be produced from LCB that are at manufacturing level. [ABSTRACT FROM AUTHOR]

Peanut processing industries generate underused by-products (skin, shell and peanut meal) which still present high economic potential. Peanut shell has adsorbent potential for water treatment, as feedstock in biofuels and nanocarbon production, as well as source of bioactive compounds. Likewise, peanut skin is a potential source of carbohydrates, proteins, lipids and bioactive compounds, while peanut meal is rich in higher digestible protein. These compounds have interesting potential as additives to food matrices. Thus, the use of peanut by-products appears as an interesting alternative for the application of biorefinery concept to enhance the value of the peanut production chain by recovering bioactive green chemicals. Considering the several attributes and the valorous chemical constituents present in these by-products, allied with wide possibilities of applications, this review describes the current status of researches dealing with peanut by-products, including aspects related to the technologies employed for the recovery of high added value products, such as, the total valorization of the peanut by-products in a biorefinery system. The proposal of a biorefinery approach to enhance the value of the peanut production chain is very promising, particularly by exploring green technologies for the recovery of valuable substances from underestimated by-products. Therefore, to expand the applications of these residual biomass, its behavior with all technologies involved, such as the use of biobased solvents, must be proper elucidated. Image 1 • Peanut by products are good sources of functional compounds, such as natural antioxidants. • Integrating green extractions methods is promising for bioactive compounds recovery. • Biorefinery concept applied to peanut by-products values peanut production chain. • Peanut extracts can be applied in food and pharmaceutical industry. [ABSTRACT FROM AUTHOR]

The setup of an economic and sustainable method to increase the production and commercialization of products from microalgae, beyond niche markets, is a challenge. Here, a cascade approach has been designed to optimize the recovery of high valuable bioproducts starting from the wet biomass of Galdieria phlegrea. This unicellular thermo-acidophilic red alga can accumulate high-value compounds and can live under conditions considered hostile to most other species. Extractions were performed in two sequential steps: a conventional high-pressure procedure to recover phycocyanins and a solvent extraction to obtain fatty acids. Phycocyanins were purified to the highest purification grade reported so far and were active as antioxidants on a cell-based model. Fatty acids isolated from the residual biomass contained high amount of PUFAs, more than those recovered from the raw biomass. Thus, a simple, economic, and high effective procedure was set up to isolate phycocyanin at high purity levels and PUFAs. [ABSTRACT FROM AUTHOR]

Microorganisms (microalgae and fungi) are currently the main sources of astaxanthin; however, this carotenoid also accumulates in crustaceans, salmonids, and birds. Seafood (derived from marine animals) processing wastes are significant sources of astaxanthin and can be employed as feed and for nutraceutical applications, where shrimp wastes are the most exploited seafood industry waste employed for astaxanthin extraction. This review discusses different sources, efficient environment-friendly extraction methods employed for astaxanthin extraction, biorefinery approaches for efficient extraction and future aspects of the application of these waste sources for commercial preparation of astaxanthin complexes. It also includes a brief overview of the advantages, disadvantages, and challenges for obtaining astaxanthin from various sources and various case scenarios integrating different biorefinery approaches. [ABSTRACT FROM AUTHOR]

Abstract The brown macroalga, Sargassum angustifolium harvested from the Persian Gulf in the summer and winter was exploited within a biorefinery approach for valuable bioproducts and ethanol production. This alga mainly contained alginate (20.9–22.4%), glucan (36.2–43.1%), lignin-like materials (i.e., polyphenols; 11.8–25.8%), and ash (43.8–35.5%). The biomass protein content was highly depended on the harvesting season, where the biomass harvested in summer and winter comprised 11.9% and 19.7% protein, respectively. The alginate was first extracted in the form of sodium alginate. Then, the residual biomass obtained during alginate extraction was used for bioethanol production through the separate hydrolysis and fermentation. The results demonstrated that 44.5 (28.0) to 53.3 (32.5) kg of ethanol and 2.4 × 102 (2.2 × 102) kg of sodium alginate could be obtained from each tone of summer (winter) algal biomass. During the extraction of alginate, a nutrient-rich extract, "macroalgal extract", was produced. This extract was successful substitute for yeast extract, which was necessary for the ethanolic fermentation. The results revealed the great potential of S. angustifolium for implementation as a source of sodium alginate, a nutrient-rich extract, and bioethanol. Highlights • The macroalga Sargassum angustifolium is a source of alginate. • The residual biomass obtained after extraction can be used for ethanol production. • Extraction of alginate acted as a kind of pretreatment. • Yeast extract can be substituted for algal extract during fermentation. • Bioethanol and sodium alginate can be produced in a biorefinery approach. [ABSTRACT FROM AUTHOR]

Recent studies have shown that pomegranate peels (PP) is a valuable source of valuable bioactive compounds, most of which can be converted into value-added products. We herein review this conversion process and provide an outline on the chemical composition of PP and the possible value-added products that can be produced from this commonly discarded agro-waste. We have also discussed its use as a substrate to produce medicinal compounds and bioactive phenolic compounds (e.g., phenolic acids, flavonoids, vitamin C, fertilizers, dietary fibers, and tannins) as well as its use in nanomaterial synthesis. Based on available evidence, it is obvious that PP has a wide variety of applications, and thus, developing an efficient system to utilize PP adequately will help to completely utilize its potential benefits. The biorefinery approach shows promising potential for efficient utilization of PP; however, additional studies should be conducted in this area. [ABSTRACT FROM AUTHOR]

Aquaculture is vital for feeding a growing population as aquatic creatures require more protein. Utilizing protein-rich biomass for feeding animals is a possible solution. Biorefinery technology can extract protein and non-protein components from biomass, creating an economically feasible value chain. This study replaced fish feed with napier grass and used a compensatory response to reduce the cost of feeding Nile tilapia. The trial involved dividing mono-sex male Nile tilapia, initially weighing between 11.10 and 13.60 g/f, into four groups with three replications based on their feeding regime. Therefore, in the study, four groups of Nile tilapia were fed different diets for 90 days. The control group (T1) received a commercial floating pellet diet throughout the trial. Group T2 and T3 received a mix of commercial floating pellet diet and napier grass in varying proportions, and group T4 was fed with only napier grass throughout the trial. The study found that groups T2 and T3 had remarkable fish growth performance, high digestibility of napier grass, and lower feed prices with the highest benefit-cost ratios. The percentage of edible flesh and Hepatosomatic Index (PT2) were higher in group T2 than T3. Cellulase activity decreased with the frequency of napier grass intake, and the amylase activity was higher in T2 than T3, which also had the highest growth performance and feed utilization. Therefore, the study suggests that the optimal feeding regimen for Nile tilapia is T2 or T3, which promotes growth and is cost-effective., Competing Interests: Competing interestsThe authors declare no competing interests., (© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2023, Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

The energy demand is increasing dramatically during last years. Due to this, biomass has been considered as an interesting alternative for renewable energy production. The objective of this work was to evaluate the production of bioethanol, biogas and electricity for using plantain pseudostem and rice husk produced as agricultural wastes in Colombia through a biorefinery scheme. The chemical characterization of these residues was carried out to get the input data for the conceptual design of fermentation, anaerobic digestion and combustion processes. Finally a techno-economic evaluation was developed to compare the potential of each process. The rice husk biorefinery showed higher yields of biogas and electricity compared to the plantain pseudostem case. In general terms, it was observed that production costs of bioethanol (0.48 USD/kg against 0.82 USD/kg), biogas (0.27 USD/m against 0.56 USD/m) and electricity (0.02 USD/kW against 0.03 USD/kW) were kept lower under a biorefinery approach compared to the stand-alone processes for the rice husk case. For plantain case all the results were negative both for stand alone and biorefinery cases. This work concluded that it is possible to take advantage of some agricultural wastes generated in Colombia under biorefinery scheme to produce bioethanol, biogas and electricity as source of energy to supply a fraction of the energetic demand in this country. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Tagatose is a rare sugar with increasing commercial interest as sweetener. Biotechnological production of d -tagatose by enzymatic isomerization of d -galactose provides an alternative to chemical processes. In the last years, l -arabinose isomerases (L-AIs) from different origins have been studied to increase the effectiveness of tagatose production. In this work, the L-AI from Bacillus subtilis, previously reported to have unique substrate specificity for l -arabinose, was expressed in Escherichia coli and studied for isomerization of d -galactose to d -tagatose. The recombinant enzyme demonstrated, for the first time, tagatose bioconversion capacity, reaching ~59% conversion. Furthermore, a sustainable tagatose production strategy was developed by using Gelidium sesquipedale red seaweed and its undervalued processing residues as source of galactose. L-AI successfully converted the galactose-rich hydrolysate, obtained from direct acid hydrolysis of seaweed, to tagatose (50.9% conversion). Additionally, the process combining autohydrolysis of G. sesquipedale and acid hydrolysis of the remaining residue allowed a full integral valorisation of polysaccharides: 13.33 g of agar, an important hydrocolloid, coupled with the production of 5.97 g of tagatose. These results confirmed that seaweed biomass and waste-derived are promising substrates for tagatose production by L-AI , contributing to the advancement of circular economy and to the actual needs of food industry. [Display omitted] • l -arabinose isomerase (L-AI) from B. subtilis was studied for tagatose production. • Recombinant L-AI can isomerize d -galactose to d -tagatose, with ~59% conversion. • Gelidium sesquipedale seaweed as a suitable source of galactose for tagatose production. • Production of tagatose and agar from red algae in a biorefinery approach. [ABSTRACT FROM AUTHOR]

• Astaxanthin accumulation was induced in Haematococcus pluvialis at 36° C. • The proposed induction method almost doubled astaxanthin accumulation rate. • An integrated process for astaxanthin, ethanol and biogas production was introduced. • 45.8 g astaxanthin and 7095.3 KJ energy per Kg of raw biomass was produced. A biorefinery approach was implemented to produce a superantixoident, i.e., astaxanthin, and biofuels, i.e., ethanol and biogas, from the biomass of microalga Haematococcus pluvialis. The hydrolysis of residual biomass obtained from astaxanthin extraction was conducted using α-amylase and glucoamylase for hydrolysis of α-glucans and a mixture of cellulases for β-glucan hydrolysis. Four different hyudrolysis processes were employed and the efficiency of 97.2% over the total residual glucan was obtained, which was then fermented to produce 0.21 g ethanol/g residual biomass. The residuals obtained from astaxanthin extraction and fermentation were anaerobically digested to produce biomethane. The yield of biomethane was 264.8 ml/g volatile solids, 2.9 fold greater than methane yield from raw microalgal biomass. Overall, the process of astaxanthin extraction and consecutive production of ethanol and biogas from H. pluvialis biomass was recognized as a promising process to produce 45.8 g astaxanthin and 7095.3 KJ energy per Kg of raw biomass. [ABSTRACT FROM AUTHOR]

• Organic waste is a renewable feedstock for biohydrogen production. • Low H 2 yield and accumulation of acid metabolites are major technical glitches. • Process integration would be required for economically viable biohydrogen production. • The closed-loop waste biorefinery approach leads to a circular bioeconomy. The present fossil fuel-based energy sector has led to significant industrial growth. On the other hand, the dependence on fossil fuels leads to adverse impact on the environment through releases of greenhouse gases. In this scenario, one possible substitute is biohydrogen, an eco-friendly energy carrier as high-energy produces. The substrates rich in organic compounds like organic waste/wastewater are very useful for improved hydrogen generation through the dark fermentation. Thus, this review article, initially, the status of biohydrogen production from organic waste and various strategies to enhance the process efficiency are concisely discussed. Then, the practical confines of biohydrogen processes are thoroughly discussed. Also, alternate routes such as multiple process integration approach by adopting biorefinery concept to increase overall process efficacy are considered to address industrial-level applications. To conclude, future perspectives besides with possible ways of transforming dark fermentation effluent to biofuels and biochemicals, which leads to circular bioeconomy, are discussed. [ABSTRACT FROM AUTHOR]

• SFE was performed to extract fucoxanthin from Phaeodactylum tricornutum. • Extraction was conducted directly from wet microalga to reduce energy and cost. • A solvent-to-solid ratio of 200:1, 20 MPa, 35 °C at 120 rpm 60 min yielded 0.69 mg/g. • Residual biomass was characterized using light microscopy and SEM-EDS analysis. • Residual cells could be potential candidate for different commercial applications. Eco-friendly, cost efficient and effective extraction methods have become significant for the industries applying zero waste principles. The two main objectives of this study were; to examine fucoxanthin extraction from wet Phaeodactylum tricornutum using subcritical fluid extraction and to characterize the residual biomass in order to determine the potential application areas. The highest fucoxanthin yield of 0.69 ± 0.05 mg/g wet cell weight was achieved using methanol with solvent-to-solid ratio of 200:1 at 120 rpm, 20 MPa pressure and at 35 °C for 60 min by subcritical extraction. Microscopy images showed that most of the cells were disrupted and intracellular components were effectively released. Based on the results of energy dispersive spectroscopy, biomass contained a mixture of organic molecules including mainly carbon (57–72%), oxygen (26–41%), magnesium (0.6–1.4%) and silica (0.4–1%) (wt%). These results make the residual biomass a potential candidate for various areas such as bioenergy, material sciences and sensor technologies. [ABSTRACT FROM AUTHOR]

In a society where the environmental conscience is gaining attention, it is necessary to evaluate the potential valorization options for agricultural biomass to create a change in the perception of the waste agricultural biomass from waste to resource. In that sense, the biorefinery approach has been proposed as the roadway to increase profit of the agricultural sector and, at the same time, ensure environmental sustainability. The biorefinery approach integrates biomass conversion processes to produce fuels, power, and chemicals from biomass. The present review is focused on the extraction of value-added compounds, anaerobic digestion, and composting of agricultural waste as the biorefinery approach. This biorefinery approach is, nevertheless, seen as a less innovative configuration compared to other biorefinery configurations, such as bioethanol production or white biotechnology. However, any of these processes has been widely proposed as a single operation unit for agricultural waste valorization, and a thoughtful review on possible single or joint application has not been available in the literature up to now. The aim is to review the previous and current literature about the potential valorization of agricultural waste biomass, focusing on valuable compound extraction, anaerobic digestion, and composting of agricultural waste, whether they are not, partially, or fully integrated.