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Water hyacinth is a rapidly growing troublesome aquatic weed plant, which causes eutrophication in water bodies and irreversible damage to the ecological system. In this work, we have investigated the water hyacinth biomass (WHB) hydrolysis efficacy of dilute alkaline (DA) pretreatment followed by biological pretreatment with white-rot fungus Alternaria alternata strain AKJK-2. The effectiveness of the dilute alkaline (DA) and biological pretreatment process on WHB was confirmed by using X-ray Diffraction (XRD) and Fourier Transform Infrared Spectrophotometer (FTIR), and was further visualized by Scanning Electron Microscope (SEM) and Confocal Laser Scanning Microscopy (CLSM). XRD spectra showed the increase in the crystallinity of pretreated samples, attributed to the elimination of amorphous components as lignin and hemicellulose. FTIR peak analysis of pre-treated WHB showed substantial changes in the absorption of cellulose functional groups and the elimination of lignin signals. Scanning electron microscopy (SEM) images showed firm, compact, highly ordered, and rigid fibril structures without degradation in the untreated WHB sample, while the pretreated samples exhibited loose, dispersed, and distorted structures. XRD indices (Segal, Landis, and Faneite), and FTIR indices [Hydrogen bond intensity (HBI); Total crystallinity index (TCI); and Lateral order crystallinity (LOI)] results were similar to the aforementioned results, and also showed an increase in the crystallinity both in alkaline and biological pretreatments. Alkaline pretreated WHB, with these indices, also showed the highest crystallinity and a crystalline allomorphs mixture of cellulose I (native) and cellulose II. These results were further validated by the CLSM, wherein fluorescent signals were lost after the pretreatment of WHB over control. Overall, these findings showed the significant potential of integrated assessment tools with chemical and biological pretreatment for large-scale utilization and bioconversion of this potential aquatic weed for bioenergy production.

Water hyacinth is a rapidly growing troublesome aquatic weed plant, which causes eutrophication in water bodies and irreversible damage to the ecological system. In this work, we have investigated the water hyacinth biomass (WHB) hydrolysis efficacy of dilute alkaline (DA) pretreatment followed by biological pretreatment with white-rot fungus Alternaria alternata strain AKJK-2. The effectiveness of the dilute alkaline (DA) and biological pretreatment process on WHB was confirmed by using X-ray Diffraction (XRD) and Fourier Transform Infrared Spectrophotometer (FTIR), and was further visualized by Scanning Electron Microscope (SEM) and Confocal Laser Scanning Microscopy (CLSM). XRD spectra showed the increase in the crystallinity of pretreated samples, attributed to the elimination of amorphous components as lignin and hemicellulose. FTIR peak analysis of pre-treated WHB showed substantial changes in the absorption of cellulose functional groups and the elimination of lignin signals. Scanning electron microscopy (SEM) images showed firm, compact, highly ordered, and rigid fibril structures without degradation in the untreated WHB sample, while the pretreated samples exhibited loose, dispersed, and distorted structures. XRD indices (Segal, Landis, and Faneite), and FTIR indices [Hydrogen bond intensity (HBI); Total crystallinity index (TCI); and Lateral order crystallinity (LOI)] results were similar to the aforementioned results, and also showed an increase in the crystallinity both in alkaline and biological pretreatments. Alkaline pretreated WHB, with these indices, also showed the highest crystallinity and a crystalline allomorphs mixture of cellulose I (native) and cellulose II. These results were further validated by the CLSM, wherein fluorescent signals were lost after the pretreatment of WHB over control. Overall, these findings showed the significant potential of integrated assessment tools with chemical and biological pretreatment for large-scale utilization and bioconversion of this potential aquatic weed for bioenergy production.

An experimental study was performed to evaluate the comparative efficiency of bio-flocculant (waste egg shell), laboratory available calcium carbonate (LACC) and alum (Al2 (SO4)3) for harvesting of unicellular microalga, Chlorella pyrenoidosa. The influence of pH on zeta potential (ζ) was also studied to explain the chemistry of flocculation process. The maximum harvesting efficiency (99%) was obtained with alum with deformities in algal cell surfaces. Waste egg-shell material is developed as a low-cost bio-flocculant for harvesting of Chlorella pyrenoidosa using 100 mg egg-shell bio-flocculant/L and 100 mg LACC/L, zeta potential analysis was completed to further understand the chemistry of harvesting efficiency over the different ranges of pH (2.0, 4.0, 6.0, 8.0, and 10.0). The optimized range for harvesting efficiency (HE) of pH is 4.0-8.0 for both flocculants. Maximal harvesting efficiency was achieved at pH 4.0 (99%) and pH 8.0 (95%) with bio-flocculant and LACC respectively. Hence, bio-flocculant based harvesting method is found as the best way to dewatering the algal biomass from aqueous medium with entire and intact algal cell surface with environment friendly and cost-effective approach.

An experimental study was performed to evaluate the comparative efficiency of bio-flocculant (waste egg shell), laboratory available calcium carbonate (LACC) and alum (Al2 (SO4)3) for harvesting of unicellular microalga, Chlorella pyrenoidosa. The influence of pH on zeta potential (ζ) was also studied to explain the chemistry of flocculation process. The maximum harvesting efficiency (99%) was obtained with alum with deformities in algal cell surfaces. Waste egg-shell material is developed as a low-cost bio-flocculant for harvesting of Chlorella pyrenoidosa using 100 mg egg-shell bio-flocculant/L and 100 mg LACC/L, zeta potential analysis was completed to further understand the chemistry of harvesting efficiency over the different ranges of pH (2.0, 4.0, 6.0, 8.0, and 10.0). The optimized range for harvesting efficiency (HE) of pH is 4.0-8.0 for both flocculants. Maximal harvesting efficiency was achieved at pH 4.0 (99%) and pH 8.0 (95%) with bio-flocculant and LACC respectively. Hence, bio-flocculant based harvesting method is found as the best way to dewatering the algal biomass from aqueous medium with entire and intact algal cell surface with environment friendly and cost-effective approach.

Fossil fuels are sharing a large portion of energy demand. Conventional energy sources emit a huge amount of greenhouse gas into the atmosphere, which creates energy and environmental challenges for the ecosystem. To fulfill the world energy demand and to support environmental as well as economic development in a sustainable way, with the utilization of technological advancement of renewable energy resources, algae are presently believed as most adaptable feedstock materials for bioenergy production. Algae has a high fixation rate of atmospheric carbon dioxide which supports to fast growth rate with high productivity per unit area in the form of renewable algal biomass. The present article aims to elaborate on the three generations of biofuels, sustainable microalgae biomass production, cultivation systems, and a wide range of growth parameters. The microalgae harvesting methods and their challenges are also discussed, with a special focus on lipid extraction methods and future r recommendations. The upstream and downstream processes of microalgae could help to harness the microalgae energy in an eco-friendly manner and will help in achieving overall sustainable development.

Fossil fuels are sharing a large portion of energy demand. Conventional energy sources emit a huge amount of greenhouse gas into the atmosphere, which creates energy and environmental challenges for the ecosystem. To fulfill the world energy demand and to support environmental as well as economic development in a sustainable way, with the utilization of technological advancement of renewable energy resources, algae are presently believed as most adaptable feedstock materials for bioenergy production. Algae has a high fixation rate of atmospheric carbon dioxide which supports to fast growth rate with high productivity per unit area in the form of renewable algal biomass. The present article aims to elaborate on the three generations of biofuels, sustainable microalgae biomass production, cultivation systems, and a wide range of growth parameters. The microalgae harvesting methods and their challenges are also discussed, with a special focus on lipid extraction methods and future r recommendations. The upstream and downstream processes of microalgae could help to harness the microalgae energy in an eco-friendly manner and will help in achieving overall sustainable development.

Biohydrogen production by dark fermentation of different waste materials is a promising approach to produce bio-energy in terms of renewable energy exploration. This communication has reviewed various influencing factors of dark fermentation process with detailed account of determinants in biohydrogen production. It has also focused on different factors such as improved bacterial strain, reactor design, metabolic engineering and two stage processes to enhance the bioenergy productivity from substrate. The study also suggest that complete utilization of substrates for biological hydrogen production requires the concentrated research and development for efficient functioning of microorganism with integrated application for energy production and bioremediation. Various studies have been taken into account here, to show the comparative efficiency of different substrates and operating conditions with inhibitory factors and pretreatment option for biohydrogen production. The study reveals that an extensive research is needed to observe field efficiency of process using low cost substrates and integration of dark and photo fermentation process. Integrated approach of fermentation process will surely compete with conventional hydrogen process and replace it completely in future.

Biohydrogen production by dark fermentation of different waste materials is a promising approach to produce bio-energy in terms of renewable energy exploration. This communication has reviewed various influencing factors of dark fermentation process with detailed account of determinants in biohydrogen production. It has also focused on different factors such as improved bacterial strain, reactor design, metabolic engineering and two stage processes to enhance the bioenergy productivity from substrate. The study also suggest that complete utilization of substrates for biological hydrogen production requires the concentrated research and development for efficient functioning of microorganism with integrated application for energy production and bioremediation. Various studies have been taken into account here, to show the comparative efficiency of different substrates and operating conditions with inhibitory factors and pretreatment option for biohydrogen production. The study reveals that an extensive research is needed to observe field efficiency of process using low cost substrates and integration of dark and photo fermentation process. Integrated approach of fermentation process will surely compete with conventional hydrogen process and replace it completely in future.