Paper mulberry fruit juice: a novel biomass resource for bioethanol production

The prospect of bamboo and non-fodder rice husk for sustainable bioethanol production

Due to the rapid industrialization globally, there is a constant increase in demand for energy, which drives up fuel prices and contributes to the depletion of fossil fuels. The rise in the use of fossil fuels results in increasing greenhouse gas emissions contributing to biodiversity loss. Thus, the development of alternative green biofuel (e.g., bioethanol) from renewable and surplus biomass resources has taken center stage as our attention is drawn to environmental concerns and energy security. However, till now, the studies pertaining to the process optimization and techno-economic analysis of bioethanol production using indigenous non-conventional biomass resources are scarcely reported for the industrial application. Henceforth, this study employed Bambusa bambos (BB) culm and non-fodder rice husk (NFRH) as the raw material due to its high holocellulose content (60-70%) for bioethanol production and based on its biomass availability in the agrarian state of Karnataka (India). Thereupon, the statistical design of experiment (DoE) method was applied for the thermo-chemical pretreatment optimization of the collected biomass resources, and the fermentation was performed using osmotolerant Angel™ yeast for the bioethanol production. Overall, the maximum reducing sugar (RS) concentration of 70.7 ± 2.6 g/L under optimal condition of 10% (w/v) loading at 121 °C for 30 min using 0.3 M sulfuric acid and bioethanol concentration of 4.7 ± 0.8 g/L (0.42 g/g RS) with conversion efficiency of 70% was obtained from the indigenous BB biomass, whereas the NFRH biomass yielded the maximal concentration of RS around 91.5 ± 2.2 g/L as per optimized conditions [15% w/v loading at 121 °C for 30 min using 0.5 M sulfuric acid] with 61% saccharification efficiency and bioethanol productivity of 5.3 ± 0.4 g/L (0.10 g/g RS). Conclusively, 61-101 L of bioethanol is estimated from 1 tonne of BB and NFRH biomass resources from the study with net energy ratio of greater than 1.0, low carbon footprint (0.14-1.97 kg carbon dioxide equivalent), bioconversion of 10-40% as per the mass-balance analysis, and production costing of less than 100 ₹/L; hence, this result provides a cost-effective sustainable solution for bioethanol production that can raise farmers income as well as enables the rural development.

Game changer for anaerobic fermentation of paper mulberry: Sucrose-loaded biochar enhancing microbial communities and lactic acid fermentation

This study investigated biochar effects, either alone or combined with sucrose, on fermentation quality, microbial communities, and in vitro rumen digestion of anaerobic fermented paper mulberry. The biochar alkaline functional groups bind to lactic acid, reducing acid inhibition and promoting Lactiplantibacillus proliferation. Owing to the low sugar content of paper mulberry, lactic acid bacteria in the biochar group primarily underwent heterofermentation, resulting in the lowest lactic and highest acetic acid contents. Treated with sucrose-loaded biochar, the increased substrate supported homofermentation, leading to the highest lactic and lowest acetic acid contents, with a 15.0 % increase in lactic acid and a 22.2 % decrease in ammoniacal nitrogen compared with the control after 75 days. In vitro rumen tests showed that the biochar-sucrose group had the highest dry matter degradation rate (45.9 %) and a 24.2 % reduction in methane emissions. Concludingly, sucrose-loaded biochar is recommended as effective for lactic acid production under anaerobic conditions.

Silage preparation and sustainable livestock production of natural woody plant

As the global population increases and the economy grows rapidly, the demand for livestock products such as meat, egg and milk continue to increase. The shortage of feed in livestock production is a worldwide problem restricting the development of the animal industry. Natural woody plants are widely distributed and have a huge biomass yield. The fresh leaves and branches of some woody plants are rich in nutrients such as proteins, amino acids, vitamins and minerals and can be used to produce storage feed such as silage for livestock. Therefore, the development and utilization of natural woody plants for clean fermented feed is important for the sustainable production of livestock product. This paper presents a comprehensive review of the research progress, current status and development prospects of forageable natural woody plant feed resources. The nutritional composition and uses of natural woody plants, the main factors affecting the fermentation of woody plant silage and the interaction mechanism between microbial co-occurrence network and secondary metabolite are reviewed. Various preparation technologies for clean fermentation of woody plant silage were summarized comprehensively, which provided a sustainable production mode for improving the production efficiency of livestock and producing high-quality livestock product. Therefore, woody plants play an increasingly important role as a potential natural feed resource in alleviating feed shortage and promoting sustainable development of livestock product.

High bioethanol titer and yield from phosphoric acid plus hydrogen peroxide pretreated paper mulberry wood through optimization of simultaneous saccharification and fermentation

The optimization of key simultaneous saccharification and fermentation (SSF) parameters for bioethanol production from phosphoric acid plus hydrogen peroxide pretreated paper mulberry wood was carried out under two isothermal scenarios; the yeast optimum and trade-off temperatures of 35 and 38 °C, respectively. The optimal conditions established for SSF at 35 °C (solid loading: 16%; enzyme dosage: 9.8 mg protein/g glucan; and yeast concentration: 6.5 g/L) achieved high ethanol titer and yield of 77.34 g/L and 84.60% (0.432 g/g), respectively. These corresponded to 1.2 and 1.3-folds increases, compared to the results of the optimal SSF at a relatively higher temperature of 38 °C. The information from this study would prove beneficial in reducing process energy demands to some extent, while also helping to achieve high levels of both ethanol concentration and yield that are desired in cellulosic ethanol production.

Polymers without Petrochemicals: Sustainable Routes to Conventional Monomers

Access to a wide range of plastic materials has been rationalized by the increased demand from growing populations and the development of high-throughput production systems. Plastic materials at low costs with reliable properties have been utilized in many everyday products. Multibillion-dollar companies are established around these plastic materials, and each polymer takes years to optimize, secure intellectual property, comply with the regulatory bodies such as the Registration, Evaluation, Authorisation and Restriction of Chemicals and the Environmental Protection Agency and develop consumer confidence. Therefore, developing a fully sustainable new plastic material with even a slightly different chemical structure is a costly and long process. Hence, the production of the common plastic materials with exactly the same chemical structures that does not require any new registration processes better reflects the reality of how to address the critical future of sustainable plastics. In this review, we have highlighted the very recent examples on the synthesis of common monomers using chemicals from sustainable feedstocks that can be used as a like-for-like substitute to prepare conventional petrochemical-free thermoplastics.

Valorization of Bombax ceiba Waste into Bioethanol Production through Separate Hydrolysis and Fermentation and Simultaneous Saccharification and Fermentation

In this study, Seed pods of B. ceiba were used as a novel, cheap, and sustainable feedstock for second-generation bioethanol production. B. ceiba waste was pretreated with NaOH under different conditions using a Box–Behnken design (BBD) with three factors and three levels. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to investigate the chemical, structural, and morphological modifications made by pretreatment. NaOH pretreatment followed by steam was more effective as it offered 60% cellulose and 9% lignin at 10% substrate loading, 5% NaOH conc., and 4 h residence time. Samples with maximum cellulose were employed for ethanol production by separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) using indigenously produced cellulase as well as commercial cellulase. HPLC analysis revealed the best saccharification (50.9%) at 24 h and the best ethanol yield (54.51 g/L) at 96 h of fermentation in SSF using commercial cellulose by Saccharomyces cerevisiae. SSF offered a better production of bioethanol from seed pods than SHF. The implications of the work support the notion that B. ceiba waste could be utilized for large-scale bioethanol production.