Successive process for efficient biovalorization of Brewers' spent grain to lignocellulolytic enzymes and lactic acid production through simultaneous saccharification and fermentation.

This study aimed to increase the value of brewers' spent grain (BSG) by using it as feedstock to produce lignocellulolytic enzymes and lactic acid (LA). Twenty-two fungal strains were screened for lignocellulolytic enzyme production from BSG. Among them, Trichoderma sp. showed the highest cellulase activity (35.84 ± 0.27 U/g-BSG) and considerably high activities of xylanase (599.61 ± 23.09 U/g-BSG) and ß-glucosidase (16.97 ± 0.77 U/g-BSG) under successive solid-state and submerged fermentation. The processes were successfully scaled up in a bioreactor. The enzyme cocktail was recovered and characterized. The maximum cellulase and xylanase activities were found at pH 5.0 and 50 °C, and the activities were highly stable at pH 4-8 and 30-50 °C. The enzyme cocktail was applied in simultaneous saccharification and fermentation of acid-pretreated BSG for LA production. The maximum LA obtained was 59.3 ± 1.0 g/L. This study has shown the efficient biovalorization of BSG, and this approach may also be applicable to other agro-industrial wastes.

A New Edible Wild Mushroom Species, Panus sribuabanensis (Panaceae, Polyporales) from Northern Thailand and Its Nutritional Composition, Total Phenolic Content, and Antioxidant Activity.

A new edible wild mushroom species, described herein as Panus sribuabanensis, was collected from local markets and natural forests located in northern Thailand. This species is characterized by its medium to large-sized basidiomata, broadly ellipsoid to ellipsoid-shaped basidiospores, dimitic hyphal system, and the absence of hyphal pegs. A molecular phylogenetic analysis of combined the internal transcribed spacer (ITS) and large subunit (nrLSU) of nuclear ribosomal DNA sequences supported the monophyly of P. sribuabanensis as a distinct lineage within the genus Panus. Full description, illustrations, color photographs, and a phylogenetic tree to show the placement of P. sribuabanensis are provided. The dried mushroom showed a nutritional composition within the range of 2.58%-2.67% for fat content, 27.10%-27.98% for protein, and 43.97%-44.10% for carbohydrates. The ethanolic extracts from this mushroom exhibited a total phenolic content ranging from 0.66 to 0.74 mg GAE/g dry weight (dw). Moreover, the antioxidant activities of ethanolic extracts evaluated by the 2,2-diphenyl-1-picrylhydrazyl (0.90-1.08 mg TE/g dw) and ferric reducing antioxidant power (0.93-1.08 mg TE/g dw) assays demonstrate higher activity compared to the 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assay (0.44-0.51 mg TE/g dw). The outcomes of this study provide significant information on the nutritional value, phenolic content, and antioxidant activity potential of this new mushroom species discovered in northern Thailand.

Employing a Plant Probiotic Actinomycete for Growth Promotion of Lettuce (Lactuca sativa L. var. longifolia) Cultivated in a Hydroponic System under Nutrient Limitation.

The consumption of lettuce is associated with an increased risk of ingesting nitrate, a naturally occurring and potentially harmful compound that can have adverse effects on human health. Hydroponic cultivation systems serve as effective tools for regulating nutrient solutions and nitrogen availability, which are essential for controlling nitrate levels. However, the techniques for reducing nutrient levels need to be appropriately calibrated based on lettuce growth responses and their interactions with the environment and growing conditions. Previous studies have demonstrated that plant probiotic actinomycetes can alleviate nutritional stress in various crops. However, there is a noticeable gap in research concerning the effects of actinomycetes on hydroponically grown lettuce, particularly under nutrient-limiting conditions. This study aimed to evaluate the effectiveness of the actinomycete Streptomyces thermocarboxydus S3 in enhancing lettuce growth in a nutrient-restricted hydroponic system. The results indicated that the detrimental effects of nutrient stress on lettuce were mitigated by the inoculation of lettuce with S. thermocarboxydus S3. This mitigation was evident in various growth parameters, including leaf count, shoot length, and the fresh and dry weights of both shoots and roots. In the presence of nutritional stress, S. thermocarboxydus S3 likely mitigated the negative effects on lettuce by reducing hydrogen peroxide levels, presumably through the synthesis of H2O2-scavenging enzymes. Furthermore, S. thermocarboxydus S3 successfully survived and colonized lettuce roots. Therefore, the inoculation of lettuce with S. thermocarboxydus S3 offers significant advantages for promoting lettuce growth in nutrient-limited hydroponic systems.

Unlocking microalgal host-exploring dark-growing microalgae transformation for sustainable high-value phytochemical production.

Microalgae have emerged as a promising, next-generation sustainable resource with versatile applications, particularly as expression platforms and green cell factories. They possess the ability to overcome the limitations of terrestrial plants, such non-arable land, water scarcity, time-intensive growth, and seasonal changes. However, the heterologous expression of interested genes in microalgae under heterotrophic cultivation (dark mode) remains a niche area within the field of engineering technologies. In this study, the green microalga, Chlorella sorokiniana AARL G015 was chosen as a potential candidate due to its remarkable capacity for rapid growth in complete darkness, its ability to utilize diverse carbon sources, and its potential for wastewater treatment in a circular bioeconomy model. The aims of this study were to advance microalgal genetic engineering via dark cultivation, thereby positioning the strain as promising dark-host for expressing heterologous genes to produce high-value phytochemicals and ingredients for food and feed. To facilitate comprehensive screening based on resistance, eleven common antibiotics were tested under heterotrophic condition. As the most effective selectable markers for this strain, G418, hygromycin, and streptomycin exhibited growth inhibition rates of 98%, 93%, and 92%, respectively, ensuring robust long-term transgenic growth. Successful transformation was achieved through microalgal cell cocultivation with Agrobacterium under complete darkness verified through the expression of green fluorescence protein and ß-glucuronidase. In summary, this study pioneers an alternative dark-host microalgal platform, using, Chlorella, under dark mode, presenting an easy protocol for heterologous gene transformation for microalgal host, devoid of the need for expensive equipment and light for industrial production. Furthermore, the developed genetic transformation methodology presents a sustainable way for production of high-value nutrients, dietary supplements, nutraceuticals, proteins and pharmaceuticals using heterotrophic microalgae as an innovative host system.

Multifarious Characterization and Efficacy of Three Phosphate-Solubilizing Aspergillus Species as Biostimulants in Improving Root Induction of Cassava and Sugarcane Stem Cuttings.

Several soil fungi significantly contribute to the enhancement of plant development by improving nutrient uptake and producing growth-promoting metabolites. In the present study, three strains of phosphate-solubilizing fungi, namely, Aspergillus chiangmaiensis SDBR-CMUI4, A. pseudopiperis SDBR-CMUI1, and A. pseudotubingensis SDBR-CMUO2, were examined for their plant-growth-promoting capabilities. The findings demonstrated that all fungi showed positive siderophore production, but only A. pseudopiperis can produce indole-3-acetic acid. All fungi were able to solubilize insoluble phosphate minerals [Ca3(PO4)2 and FePO4] by producing phosphatase enzymes and organic acids (oxalic, tartaric, and succinic acids). These three fungal species were grown at a water activity ranging from 0.837 to 0.998, pH values ranging from 4 to 9, temperatures between 4 and 40 °C, and 16-17% NaCl in order to evaluate their drought, pH, temperature, and salt tolerances, respectively. Moreover, the results indicated that A. pseudopiperis and A. pseudotubingensis were able to tolerate commercial insecticides (methomyl and propargite) at the recommended dosages for field application. The viability of each fungal strain in the inoculum was higher than 50% at 4 and 20 °C after 3 months of storage. Subsequently, all fungi were characterized as plant-growth-promoting strains by improving the root inductions of cassava (Manihot esculenta Crantz) and sugarcane (Saccharum officinarum L.) stem cuttings in greenhouse experiments. No symptoms of plant disease were observed with any of the treatments involving fungal inoculation and control. The cassava and sugarcane stem cuttings inoculated with fungal strains and supplemented with Ca3(PO4)2 exhibited significantly increased root lengths, shoot and root dry biomasses, chlorophyll concentrations, and cellular inorganic phosphate contents. Therefore, the application of these phosphate-solubilizing fungi is regarded as a new frontier in the induction of roots and the promotion of growth in plants.

Value-added green biorefinery co-products from ultrasonically assisted DES-pretreated Chlorella biomass.

This study pursued the goal of creating value-added co-products through an environmentally friendly biorefinery approach, employing ultrasonically assisted deep eutectic solvent (DES)-pretreated Chlorella biomass. The primary focus was on generating enriched biodiesel feedstock with exceptional fuel properties and developing hydroponic biofertilizer. The results demonstrated the effectiveness of a two-step process involving a 5-minute ultrasound-assisted DES pretreatment followed by ultrasound-assisted solvent extraction, which efficiently extracted lipids from Chlorella biomass, yielding biodiesel-quality lipids with good cetane number (59.42) and high heating value (40.11 MJ/kg). Notably, this two-step approach (78.04 mg-lipid/g-microalgal biomass) led to a significant 2.10-fold increase in lipid extraction compared to a one-step process (37.15 mg-lipid/g-microalgal biomass) that combined ultrasound-assisted DES pretreatment and solvent extraction. Importantly, the aqueous extract derived from lipid-extracted microalgal biomass residues (LMBRs) showed promise as a component in hydroponic biofertilizer production, supporting lettuce growth in hydroponic deep water culture system. Consequently, microalgae biorefinery co-products hold tremendous potential in enhancing the profitability and sustainability of interconnected sectors, encompassing renewable energy, agriculture, and the environment.

Microalgae as tools for bio-circular-green economy: Zero-waste approaches for sustainable production and biorefineries of microalgal biomass.

Microalgae are promising organisms that are rapidly gaining much attention due to their numerous advantages and applications, especially in biorefineries for various bioenergy and biochemicals. This review focuses on the microalgae contributions to Bio-Circular-Green (BCG) economy, in which zero-waste approaches for sustainable production and biorefineries of microalgal biomass are introduced and their possible integration is discussed. Firstly, overviews of wastewater upcycling and greenhouse gas capture by microalgae are given. Then, a variety of valuable products from microalgal biomass, e.g., pigments, vitamins, proteins/peptides, carbohydrates, lipids, polyunsaturated fatty acids, and exopolysaccharides, are summarized to emphasize their biorefinery potential. Techno-economic and environmental analyses have been used to evaluate sustainability of microalgal biomass production systems. Finally, key issues, future perspectives, and challenges for zero-waste microalgal biorefineries, e.g., cost-effective techniques and innovative integrations with other viable processes, are discussed. These strategies not only make microalgae-based industries commercially feasible and sustainable but also reduce environmental impacts.

Innovative Eco-Friendly Microwave-Assisted Rapid Biosynthesis of Ag/AgCl-NPs Coated with Algae Bloom Extract as Multi-Functional Biomaterials with Non-Toxic Effects on Normal Human Cells.

Harmful algal blooms impact human welfare and are a global concern. Sargassum spp., a type of algae or seaweed that can potentially bloom in certain regions of the sea around Thailand, exhibits a noteworthy electron capacity as the sole reducing and stabilizing agent, which suggests its potential for mediating nanoparticle composites. This study proposes an eco-friendly microwave-assisted biosynthesis (MAS) method to fabricate silver nanoparticles coated with Sargassum aqueous extract (Ag/AgCl-NPs-ME). Ag/AgCl-NPs-ME were successfully synthesized in 1 min using a 20 mM AgNO3 solution without additional hazardous chemicals. UV-visible spectroscopy confirmed their formation through a surface plasmon resonance band at 400-500 nm. XRD and FTIR analyses verified their crystalline nature and involvement of organic molecules. TEM and SEM characterization showed well-dispersed Ag/AgCl-NPs-ME with an average size of 36.43 nm. The EDS results confirmed the presence of metallic Ag+ and Cl- ions. Ag/AgCl-NPs-ME exhibited significant antioxidant activity against free radicals (DPPH, ABTS, and FRAP), suggesting their effectiveness. They also inhibited enzymes (tyrosinase and ACE) linked to diseases, indicating therapeutic potential. Importantly, the Ag/AgCl-NPs-ME displayed remarkable cytotoxicity against cancer cells (A375, A549, and Caco-2) while remaining non-toxic to normal cells. DNA ladder and TUNEL assays confirmed the activation of apoptosis mechanisms in cancer cells after a 48 h treatment. These findings highlight the versatile applications of Ag/AgCl-NPs-ME in food, cosmetics, pharmaceuticals, and nutraceuticals.

Changes in Physicochemical Characteristics and Antioxidant Activities of Dried Shiitake Mushroom in Dry-Moist-Heat Aging Process.

Shiitake mushrooms are prized for their unique flavor and bioactive properties. While there has been extensive research on drying methods, a comprehensive investigation of the effects of drying parameters in the dry-moist-heat system on shiitake quality is still needed. This study aimed to investigate the effects of dry-moist-heat aging on dried shiitake mushrooms comprehensively. Four aging temperatures, specifically 50, 60, 70, and 80 °C, were applied to the mushrooms, maintaining a constant humidity level of 75% RH and aging duration of 20 days. Color analysis revealed a progressive decrease in measured values as aging temperature increased, indicating noticeable changes in visual characteristics. Regarding amino acid composition, glutamic acid was found to be the predominant amino acid in shiitake mushrooms in the range of 90.29-467.42 mg/100 g. However, aging led to a reduction in overall amino acid content, with higher aging temperatures resulting in greater decline. Similarly, the equivalent umami content (EUC) also decreased (from 123.99 to 7.12 g MSG/100 g) with the increase in aging temperatures up to 80 °C, suggesting a decline in the overall umami taste sensation. Interestingly, despite the reduction in amino acid levels and umami content, the aging process positively impacted the phenolic compounds and the antioxidant activity of dried shiitake mushrooms. The antioxidative abilities of all aged mushroom extracts for DPPH, ABTS, and FRAP ranged from 65.01 to 81.39 µg TE/mL, 87.04 to 258.33 µg GAE/mL, and 184.50 to 287.68 µg FeSO4/mL, respectively. The utilization of aged temperature at 60 °C for 20 days with controlled relative humidity (~75%) should be a suitable aging condition of this edible mushroom with both antioxidant and umami qualities. Nevertheless, the control sample demonstrated higher levels of amino acid content and EUC compared to the aged samples. Conversely, the aged samples exhibited higher polyphenol content and greater antioxidant activity. Depending on specific requirements, these powders can be used in food formulation as flavor enhancers for control samples or as enriching agents for polyphenols and antioxidant activity in matured samples. Therefore, all of the powders obtained have potential applications in the field of nutrition.

Optimization of Melanin Production by Streptomyces antibioticus NRRL B-1701 Using Arthrospira (Spirulina) platensis Residues Hydrolysates as Low-Cost L-tyrosine Supplement.

Melanin is a functional pigment that is used in various products. It can be produced by Streptomyces antibioticus NRRL B-1701 when supplemented with L-tyrosine. Arthrospira (Spirulina) platensis is a cyanobacterium with high protein content, including the protein phycocyanin (PC). During PC's extraction, biomass residues are generated, and these residues still contain various amino acids, especially L-tyrosine, which can be used as a low-cost supplement for melanin production. Thus, this study employed a hydrolysate of A. platensis biomass residue for L-tyrosine substitution. The effects of two drying methods, namely, lyophilization and dying via a hot air oven, on the proximate composition and content of L-tyrosine in the biomass residue were evaluated. The highest L-tyrosine (0.268 g L-tyrosine/100 g dried biomass) concentration was obtained from a hot-air-oven-dried biomass residue hydrolysate (HAO-DBRH). The HAO-DBRH was then used as a low-cost L-tyrosine supplement for maximizing melanin production, which was optimized by the response surface methodology (RSM) through central composite design (CCD). Using the RSM-CCD, the maximum level of melanin production achieved was 0.24 g/L, which is approximately four times higher than it was before optimization. This result suggests that A. platensis residue hydrolysate could be an economically feasible and low-cost alternative source of L-tyrosine for the production of melanin.

Termite Mushrooms (Termitomyces), a Potential Source of Nutrients and Bioactive Compounds Exhibiting Human Health Benefits: A Review.

Termite mushrooms have been classified to the genus Termitomyces, family Lyophyllaceae, order Agaricales. These mushrooms form a mutualistic association with termites in the subfamily Macrotermitinae. In fact, all Termitomyces species are edible and have unique food value attributed to their texture, flavour, nutrient content, and beneficial mediational properties. Additionally, Termitomyces have been recognized for their ethno-medicinal importance in various indigenous communities throughout Asia and Africa. Recent studies on Termitomyces have indicated that their bioactive compounds have the potential to fight against certain human diseases such as cancer, hyperlipidaemia, gastroduodenal diseases, and Alzheimer's. Furthermore, they possess various beneficial antioxidant and antimicrobial properties. Moreover, different enzymes produced from Termitomyces have the potential to be used in a range of industrial applications. Herein, we present a brief review of the current findings through an overview of recently published literature involving taxonomic updates, diversity, distribution, ethno-medicinal uses, nutritional value, medicinal importance, and industrial implementations of Termitomyces, as well as its socioeconomic importance.

Naturally Occurring Functional Ingredient from Filamentous Thermophilic Cyanobacterium Leptolyngbya sp. KC45: Phytochemical Characterizations and Their Multiple Bioactivities.

Cyanobacteria are rich in phytochemicals, which have beneficial impacts on the prevention of many diseases. This study aimed to comprehensively characterize phytochemicals and evaluate multifunctional bioactivities in the ethanolic extract of the cyanobacterium Leptolyngbya sp. KC45. Results found that the extract mainly contained chlorophylls, carotenoids, phenolics, and flavonoids. Through LC-ESI-QTOF-MS/MS analysis, 38 phenolic compounds with promising bioactivities were discovered, and a higher diversity of flavonoids was found among the phenolic compounds identified. The extract effectively absorbed the harmful UV rays and showed high antioxidant activity on DPPH, ABTS, and PFRAP. The extract yielded high-efficiency inhibitory effects on enzymes (tyrosinase, collagenase, ACE, and α-glucosidase) related to diseases. Interestingly, the extract showed a strong cytotoxic effect on cancer cells (skin A375, lung A549, and colon Caco-2), but had a much smaller effect on normal cells, indicating a satisfactory level of safety for the extract. More importantly, the combination of the DNA ladder assay and the TUNEL assay proved the appearance of DNA fragmentation in cancer cells after a 48 h treatment with the extract, confirming the apoptosis mechanisms. Our findings suggest that cyanobacterium extract could be potentially used as a functional ingredient for various industrial applications in foods, cosmetics, pharmaceuticals, and nutraceuticals.

Mechanical, Physical, and Chemical Properties of Mycelium-Based Composites Produced from Various Lignocellulosic Residues and Fungal Species.

Mycelium-based composites (MBCs) are characterized as biodegradable materials derived from fungal species. These composites can be employed across a range of industrial applications that involve the manufacturing of packaging materials as well as the manufacturing of buildings, furniture, and various other household items. However, different fungal species and substrates can directly affect the functional properties of MBCs, which ultimately vary their potential to be used in many applications. In this study, the mechanical, physical, and chemical properties of MBCs made from four different fungal species (Ganoderma fornicatum, Ganoderma williamsianum, Lentinus sajor-caju, and Schizophyllum commune) combined with three different types of lignocellulosic residues (sawdust, corn husk, and rice straw) were investigated. The results indicate that differences in both the type of lignocellulosic residues and the fungal species could affect the properties of the obtained MBCs. It was found that the MBCs obtained from sawdust had the highest degree of density. Moreover, MBCs obtained from S. commune with all three types of lignocellulosic residues exhibited the highest shrinkage value. The greatest degree of water absorption was observed in the MBCs obtained from rice straw, followed by those obtained from corn husk and sawdust. Additionally, the thermal degradation ability of the MBCs was observed to be within a range of 200 to 325 °C, which was in accordance with the thermal degradation ability of each type of lignocellulosic residue. The greatest degrees of compressive, flexural, impact, and tensile strength were observed in the MBCs of G. williamsianum and L. sajor-caju. The results indicate that the MBCs made from corn husk, combined with each fungal species, exhibited the highest values of flexural, impact, and tensile strength. Subsequently, an analysis of the chemical properties indicated that the pH value, nitrogen content, and organic matter content of the obtained MBCs were within the following ranges: 4.67−6.12, 1.05−1.37%, and 70.40−86.28%, respectively. The highest degree of electrical conductivity was observed in MBCs obtained from rice straw. Most of the physical and mechanical properties of the obtained MBCs were similar to those of polyimide and polystyrene foam. Therefore, these composites could be used to further develop relevant strategies that may allow manufacturers to effectively replace polyimide and polystyrene foams in the future.

Amazing Fungi for Eco-Friendly Composite Materials: A Comprehensive Review.

The continually expanding use of plastic throughout our world, along with the considerable increase in agricultural productivity, has resulted in a worrying increase in global waste and related environmental problems. The reuse and replacement of plastic with biomaterials, as well as the recycling of agricultural waste, are key components of a strategy to reduce plastic waste. Agricultural waste is characterized as lignocellulosic materials that mainly consist of cellulose, hemicellulose, and lignin. Saprobe fungi are able to convert agricultural waste into nutrients for their own growth and to facilitate the creation of mycelium-based composites (MBC) through bio-fabrication processes. Remarkably, different fungal species, substrates, and pressing and drying methods have resulted in varying chemical, mechanical, physical, and biological properties of the resulting composites that ultimately vary the functional aspects of the finished MBC. Over the last two decades, several innovative designs have produced a variety of MBC that can be applied across a range of industrial uses including in packaging and in the manufacturing of household items, furniture, and building materials that can replace foams, plastics, and wood products. Materials developed from MBC can be considered highly functional materials that offer renewable and biodegradable benefits as promising alternatives. Therefore, a better understanding of the beneficial properties of MBC is crucial for their potential applications in a variety of fields. Here, we have conducted a brief review of the current findings of relevant studies through an overview of recently published literature on MBC production and the physical, mechanical, chemical, and biological properties of these composites for use in innovative architecture, construction, and product designs. The advantages and disadvantages of various applications of mycelium-based materials (MBM) in various fields have been summarized. Finally, patent trends involving the use of MBM as a new and sustainable biomaterial have also been reviewed. The resulting knowledge can be used by researchers to develop and apply MBC in the form of eco-friendly materials in the future.

Dual-bioaugmentation strategy to enhance the formation of algal-bacteria symbiosis biofloc in aquaculture wastewater supplemented with agricultural wastes as an alternative nutrient sources and biomass support materials.

This study performs an integrated evaluation of the formation and distribution of algal-bacterial bioflocs in aquaculture wastewater supplemented with agricultural waste, together with an assessment of their behavior in the microbial community and of the water quality of the system in which a new bioaugmentation strategy was applied. Results indicated that the dual bioaugmentation strategy via the consortium addition of bacteria and microalgae had the highest formation performance, providing the most compact biofloc structure (0.59 g/L), excellent settleability (71.91%), and a large particle diameter (4.25 mm). The fed-batch supplementation of molasses and rice bran, in terms of changes in the values of COD, NH4+, NO3-, and PO43-, stimulated the formation of biofloc through algal-bacterial bioflocs and microbe-rice bran complexes within a well-established microbial community. These findings provide new insight into the influence of bioaugmentation on the formation of an innovative algal-bacterial biofloc.

Lipid Profile, Antioxidant and Antihypertensive Activity, and Computational Molecular Docking of Diatom Fatty Acids as ACE Inhibitors.

Diatoms, as single cell eukaryotic microalgae, are rich sources of lipids, which have either beneficial or detrimental effects on the prevention and treatment of many diseases. Gas chromatography-mass spectrometry (GC-MS) identified diatom lipids with high levels of essential fatty acids (EFAs), especially polyunsaturated FAs (PUFAs) containing both omega-3 and omega-6. Nutritional values of FAs indicated possible applications in the pharmaceutical, nutraceutical, and functional food industries. Diatom FAs showed antioxidative potential on harmful radicals by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) scavenging, with high inhibition of the angiotensin-converting enzyme (ACE) that causes cardiovascular disease (CVD) and hypertension. A computational molecular docking simulation confirmed the inhibition mechanisms of FAs on ACE, with comparable levels of binding free energy to chemically synthesized ACE drugs. Findings suggested that diatom lipids showed potential for use as alternative ACE inhibitors or food supplement for CVD prevention.

Enhanced production of microalgal biomass and lipid as an environmentally friendly biodiesel feedstock through actinomycete co-culture in biogas digestate effluent.

In this study, an innovative approach to enhance the production of microalgal biomass and lipid as a promising sustainable feedstock for biodiesel was proposed using an actinomycetes co-culture with microalgae in the biogas digestate effluent (BDE) that can be employed as an environmentally friendly and cost-effective strategy. Among tested actinomycete isolates, Piscicocus intestinalis WA3 produced indole-3-acetic acid and siderophores as algal growth promoting agents and showed effective lipid accumulation with satisfying fatty acids composition. During co-cultivation of P. intestinalis WA3 with microalga Tetradesmus obliquus AARL G022 in the BDE, biomass production, chlorophyll a content, and lipid productivity were significantly increased by 1.30 folds, 1.39 folds, and 1.55 folds, respectively, compared to microalgae monoculture. The accumulated lipids contained long-chain fatty acids with better fuel properties that could potentially be used as biodiesel feedstock. The overall results evidenced that actinomycete co-culture would contribute greatly to the cost-effective production of environmental-friendly microbial-based biofuel.

Performance of Actinobacteria isolated from rhizosphere soils on plant growth promotion under cadmium toxicity.

This work aimed to evaluate the potential use of plant growth-promoting actinobacteria (PGPA) for enhanced cadmium (Cd) phytoremediation and plant growth. Forty-two actinobacteria were isolated from rhizosphere soils in Thailand. Among isolates tested, only Streptomyces phaeogriseichromatogenes isolate COS4, showed the high ability to produce siderophores as a plant growth stimulant and had a strong Cd tolerance potential. The significance of siderophores production and Cd tolerance ability under different Cd concentrations suggests the potential of isolate COS4 to work effectively. Plant culture revealed that the significant increase in root length, root to tip length, and total dried weight of sunflower were obtained after 2 h incubation of sunflower seeds with isolate COS4. The efficiency of Cd uptake was found to range between 42.3 and 61.3%. Translocation factor results confirmed that plant growth promoting S. phaeogriseichromatogenes isolate COS4-assisted phytoremediation can be considered as Cd absorbents for the restoration of polluted sites due to high translocation values.

Designation of rice cake starters for fermented rice products with desired characteristics and fast fermentation.

This study aimed to control characteristics of fermented rice products by using functional fungi and yeasts isolated from traditional rice cake starters in Thailand. Amylolytic fungi, amylolytic yeasts, alcoholic yeasts and aromatic yeasts were isolated from rice cake starters through different isolation protocols. Among the protocols tested, the enrichment in rice cake fermentation prior to isolation was the most suitable protocol for isolation of amylolytic fungi from all rice cake starters. While the enrichment in submerged fermentation prior to isolation could increase the numbers of yeast isolates. The selected amylolytic fungus and amylolytic yeast were identified as Rhizopus oryzae F63S and Saccharomycopsis fibuligera Y71R, respectively. The yeast with high production of ethanol and aromatic ester was identified as Pichia anomala Y11E. Fermented rice cakes with different characteristics were prepared using various combinations of fungi and yeast. The combination of R. oryzae F63S with S. fibuligera Y71R exhibited strong amylolytic activity and produced an extra sweet fermented rice cake. While the combination of R. oryzae F63S with P. anomala Y11E showed higher alcoholic and aromatic flavors. Moreover, the pure yeast P. anomala Y11E added with commercial amylase has been proven as an innovative starter for fast fermentation. This concept may contribute greatly to the further development of fermented food with desired properties at industrial level.

Immobilized oleaginous microalgae as effective two-phase purify unit for biogas and anaerobic digester effluent coupling with lipid production.

Oleaginous microalga Scenedesmus sp. was immobilized in alginate-gel beads and applied as two-phase purify unit for biogas and anaerobic digester effluent from palm oil mill. Optimal microalgal cell concentration and bead volume ratio were 106 cells mL-1 and 25% v/v, respectively. The use of 20% effluent and light intensity at 128 µmol·proton·m-2 s-1 most promoted CO2 removal by immobilized microalgae and achieved the maximum CO2 removal rate of 4.63 kg-CO2 day-1 m-3. This process upgraded methane content in biogas (>95%) and completely remove nitrogen and phosphorus in the effluent. After process operation, 2.98 g L-1 microalgal biomass with 35.92% lipid content were recovered by simple sieving method. Microalgal lipids are composed of C16-C18 (>98%) with prospect high cetane number and short ignition delay time. This study has shown the promising biorefinery concept which is effective not only in CO2 fixation, biogas upgrading and pollutant removal but also cost-effective production of microalgae-based biofuel.