Waste and Biomass Valorization

This study attempted to find potential effective thermotolerant microorganisms producing complex enzymes for use in the hydrolyzing empty fruit bunch (EFB) to reduce cost of enzyme and enhance the efficiency of saccharification. The enrichment process at 45 °C was employed as a strategy to obtain four effective thermotolerant microorganisms. Streptomyces thermocarboxydus ME742, Bacillus subtilis ME751 and Bacillus amyloliquefaciens ASB/TRE produced the highest activity of xylanase (226.2 U/mL), CMCase (3.84 U/mL) and FPase (69.55 U/mL), respectively, while Aspergillus fumigatus A4112 exhibited the highest specific activity of xylanase (637.9 U/mg), CMCase (5.55 U/mg) and FPase (21.58 U/mg). Xylanase of isolated ME742 and A4112, CMCase of isolated ASB/TRE, FPase of isolated ME742, ME751 and ASB/TRE possessed thermostability with 80% remaining activity at 60 °C after 1 h incubation. These four strains were capable to reduce 49–78% (w/w) lignin in raw EFB with simultaneous enzyme production. The EFB residue was reused as substrate for saccharification with the highest amount of reducing sugar using the crude enzymes from S. thermocarboxydus ME742 (9.24 mg/g EFB). The sugar was 3.76 and 3.61 fold higher than that obtained from saccharification of acid- and alkaline-pretreated EFB, respectively. Moreover, the crude enzymes from A. fumigatus A4112 and B. amyloliquefaciens ASB/TRE hydrolyzed palm oil mill effluent (POME) to generate high yield of reducing sugar (61.01–64.63 mg/g TS-POME). Therefore, these selected strains were considered as the potent biological tool applicable in the bioconversion of oil palm biomass to fermentable reducing sugars.

Purpose Effectual waste utilization from plant as well as marine biomass has gained tremendous importance with reference to sustainability. The valorization of marine biomass produces value added compounds containing not only C, H, O but also renewable N atom in the skeleton which widens the scope for its exploration which may prove to be economically beneficial to the society. Heterogeneous catalytic transformation of marine biomass i.e. N-acetyl glucosamine (NAG) to N-substituted aromatic heterocyclic furan derivatives is reported for the very first time. Cost effective and stable metal oxide catalysts were deployed for the transformation. Catalyst screening study showed that La2O3 was found to be an excellent catalyst for N-acetyl glucosamine (NAG) dehydration which mainly produced 3-acetamidofuran (3AF). Methods The physicochemical properties of the metal oxide catalyst were investigated by various techniques such as XRD, FTIR, MeOH-FTIR, TPD, SEM, N2 sorption studies and HR-TEM analysis for structure activity relationship. Results The effect of various reaction parameters such as catalyst concentration, reaction temperature, reaction time and solvent effect on dehydration of N-acetyl glucosamine has been studied in detail for higher yields. The results revealed that the presence of weak basic sites which are Brønsted in nature and nano pores present on the surface were responsible for improved dehydration of the chitin biomass to selectively yield 3-acetamidofuran (3AF). La2O3 catalyst showed optimum 50% 3AF yield from N-acetyl glucosamine at 180 °C in 3 h. Conclusion Efficacious exploitation of marine biomass to value added chemicals using heterogeneous catalysts can be extensively exploited. Separation of N-substituted heterocyclic aromatics is the most innovative aspect of the current study. Thus, utilization of heterogeneous catalyst and renewable biomass as a raw material indicates a transition towards more sustainable and greener approach. With reference to valorization of biomass waste towards sustainability. We report for the first time heterogeneous catalytic transformation of marine biomass i.e. N-acetyl glucosamine (NAG) over La2O3 catalyst to yield 50% 3-acetamido furan (3AF) and 20% 3-acetamido-5-acetylfuran with 100% NAG conversion. The superior performance of La2O3 catalyst was attributed to the presence of brønsted basicity and nanopores present at catalysts surface.

Urban leaf litter occurs in significant, yet unknown, quantities and is regularly disposed of or composted. Instead, it could be widely used as a regional resource for solid fuel production. Samples of five tree genera (Acer, Aesculus, Fagus, Tilia, Quercus) were taken after leaf abscission and analyzed for elemental composition (C, H, N, S, Ca, Cl, Cu, K, Mg, Mn, Na, P, Zn) and ash slagging behavior. Ash content was generally high (13.8 % dry matter) due to soil adherence. Mashing and subsequent mechanical separation significantly reduced concentrations of Cl, K and S in the resulting press cake, resulting in concentrations of 0.01, 0.36 and 0.07 % dry matter respectively (mass flow into press cake: 25.6, 51.54 and 73.83 %, respectively). Average lower heating value of the press cake was 19.22 MJ kg−1 dry matter (ash free). Processing elevated the mean ash softening temperature from 1233 °C for raw materials to 1245 °C for press cakes. However, processing did not alter ash content, which indicates that additional washing is necessary for a further increase in fuel quality.

The manufacture of acrylic acid from glycerol presents an intriguing alternative for this molecule, which has significant industrial importance. A surplus of glycerol was produced as waste during the transesterification process as a result of the increase in biodiesel production. The key difficulty is finding a catalyst that can catalyze a certain oxydehydration reaction to produce acrylic acid while maintaining an appropriate balance between acid and metal sites. For the conversion of glycerol to acrylic acid, metal loaded zeolites, heteropoly acids, metal oxides, and phosphates have all been successfully investigated. In a fixed bed reactor run between 280 and 360 °C, several vanadium (V) integrated zeolite beta (V-ß) catalysts with variable V loadings (0.6–5.0 wt%) were synthesized and tested for the gas-phase glycerol oxydehydration process. It has been demonstrated that vanadium is essential for transforming the intermediate acrolein molecule into acrylic acid. The V2.5-ß catalyst had the best acrylic acid selectivity (39%) due to its adequate pore diameter (130 Å), and moderate acidity (1.13 mmol/g). Loss of accessible Bronsted acid sites and increased COx generation were linked to worse activity at greater V loading. The effects of feed glycerol-oxygen ratio and reaction temperature (280–360 °C) were satisfactorily proven. The glycerol conversion improved and the acrylic acid selectivity peaked at 340 °C. The alkaline treatment and small internal pore diameters to reduce the deposition of carbonaceous deposits made the V2.5-ß catalyst an extremely active and selective catalyst for the reaction that also showed good stability over time.

To find a multifunctional lignocellulolytic enzyme-producing strain, ten bacterial isolates from paper mill wastewater were tested for their carboxymethyl cellulose (CMC) hydrolytic ability. Bacillus sp. TPF-1, which exhibits the highest hydrolytic ability, was selected to produce lignocellulolytic enzymes using various biomass types as carbon sources. The highest CMCase (9.12 U/mL) and xylanase (102.55 U/mL) activities were obtained by green algae, and the maximum laccase activity (7037.28 U/L) was induced by Sargassum fusiforme. CMCase and xylanase showed the highest activities at 55 and 50 °C, respectively, with the same optimum pH of 5.4. The laccase exhibited optimum temperature of 40 °C and retained 60% more activity at 80 °C in extreme acid conditions (pH 2.2). To explore the multiple applications of these enzymes, crude enzymes induced by green algae were used to saccharify untreated algae. The reducing sugar produced by crude enzymes and commercial cellulase was 23 and 14% higher than that of the control, respectively, and it was 48% higher using crude enzymes with commercial cellulase (72 h). Additionally, the laccase induced by S. fusiforme was tested to decolorize two chemical dyes under an acidic condition (pH 2.2). The highest decolorization rates were 56.13 and 62.14% for Coomassie brilliant blue R-250 and Congo Red, respectively, in the presence of hydroxybenzotriazole monohydrate.

In Brazil, the production and consumption of palm heart, especially from the Bactris gasipaes Kunth, generates a large number of lignocellulosic by-products. This study reports the obtainment of xylooligosaccharides (XOS) from xylans extracted from these residues. Xylans from peach palm waste (inner sheath and peel) were extracted using a mild alkali treatment with recovery yields of 82% and 80%, respectively. XOS were obtained through enzymatic hydrolysis employing a commercial xylanase with yields from xylan inner sheath and xylan peel of 50.1% and 48.8%, respectively. The antioxidant potential of XOS was measured employing five of the most commonly used procedures. In overall terms, the XOS from the xylans of peach palm wastes showed higher antioxidant capacity than the XOS obtained from the commercial xylans. The chemical structures of the XOS were determined by mass spectrometry (ESI–MS). The ESI–MS spectra suggest that XOS with grouped xylose or arabinose units ranging from 2 to 5 (differing by 132 Da) and as sodium adduct ions [M + Na]+ in the range of 100–1000 m/z. These results indicate that peach palm wastes can be explored to XOS production, which could be applied as natural antioxidants in functional food and pharmaceutical preparations.

Due to the contradiction between the discontinuity of agricultural production and continuity of industrial processing, the collection, storage and transformation of lignocellulosic biomass has become a basic problem in ensuring its sustainable development and large-scale utilization. Two broad methodologies for storage of LCB, dry and wet storage, are introduced. Process parameters including chemical reactions, microbial growth, temperature, and oxygen content, are analyzed in silage of different stages and with different microbial silage additives for the solid anaerobic treatment. Based on the results, we propose a quality evaluation system, encompassing sensory evaluation, organic acid content, soluble carbohydrate content, pH value and bacterial diversity, which can be used as criteria for judging the success of the microbial silage process. Finally, the research on solid-state anaerobic microbial silage pretreatment in biogas and ethanol conversion is summarized, and an optimized method for highly-efficient biochemical transformation of LCB is proposed based on the available findings.