Microbial communities that drive the degradation of flax pectin and hemicellulose during dew retting with Bacillus licheniformis HDYM-04 and Bacillus subtilis ZC-01 addition

An efficient preparation process of sisal fibers via the specialized retting microorganisms: Based on the ideal combination of degumming-related enzymes for the effective removal of non-cellulosic macromolecules

Bioaugmentation retting with the specialized pectinolytic and xylanolytic microorganisms can accelerate the removal of non-cellulosic macromolecules around plant fibers, thus shortening retting time and facilitating fiber quality. Currently, few specialized microorganisms have been explored for the retting of sisal fibers. The present study excavated the retting fungi including Aspergillus micronesiensis HD 3-6, Penicillium citrinum HD 3-12-3, and Cladosporium sp. HD 4-13 from the region-specific soil samples of planting sisal, and investigated their bioaugmentation retting effects on raw sisal leaves. Results showed that combination of the three fungi achieved the most excellent degumming efficiency (13.69 % of residual gum in sisal fibers) and the highest fiber yield (4.47 %). Furthermore, this fungi combination had the ideal enzymatic hydrolysis features with high activities of pectinase, xylanase and mannanase whereas a low activity of cellulase during the whole retting process, thus endowing the prepared sisal fibers with the lowest mass percentage of non-cellulosic macromolecules (9.76 wt%) and the highest cellulose content (89.23 wt%). SEM and FT-IR analysis further verified that the non-cellulosic substances around sisal fibers were efficiently removed. In summary, the consortia of the three fungi achieved ideal degumming-related enzymes for the removal of non-cellulosic macromolecules, thus acquiring the efficient preparation of sisal fibers.

Effect of combined bacteria on the flax dew degumming process: Substance degradation sequence and changes in functional bacteria taxa

In this study, 16S rDNA high-throughput sequencing, Fourier transform infrared spectroscopy, and two-dimensional correlation spectroscopy techniques were used to analyze the mechanisms driving the sequence of degradation of gummy substances by the microbial community and hydrolytic enzymes during the flax dew degumming process. The results revealed that the inoculation of combined bacteria induced quorum sensing, modulated hydrolytic enzyme production, and reshaped the community structure. Lignin-degraded genera (Pseudomonas and Sphingobacterium) were enriched, and the relative abundances of pectin- and cellulose-degraded genera (Chryseobacterium) decreased in the early degumming stages. Hemicellulose-degraded genera (Brevundimonas) increased over the degumming time. Moreover, the abundance of lignin hydrolytic enzymes improved in the early stages, while the abundance of pectin hydrolytic enzymes increased at the end of degumming. Various types of functional bacteria taxa changed the sequence of substance degradation. Electron scanning microscopy and differential scanning calorimetry results indicated that the degumming, facilitated by the inoculation of combined bacteria, was nearly completed by 21 d. The fibers exhibited smoother and more intact properties, along with higher thermal stability, as indicated by a melting temperature of 71.54 °C. This study provides a reference for selecting precise degumming bacterial agents to enhance degumming efficiency.

Lignocellulosic biomass fertilizers: Production, characterization, and agri-applications

The growing focus on sustainable agriculture and optimal resource utilization has spurred investigations into lignocellulosic biomass as a potential source for producing environmentally friendly fertilizers. This paper reviews recent advancements in the production and application of innovative fertilizers derived from lignocellulose. It highlights potential in enhancing agricultural productivity and reducing environmental impacts such as carbon footprint and water pollution. The paper outlines various methods for conversion, highlighting the unique advantages of chemical, enzymatic, and microbiological processes, for converting lignocellulosic biomass into nutrient-rich fertilizers. The study compares the efficacy of lignocellulosic fertilizers to traditional fertilizers in promoting crop growth, enhancing soil health, and reducing nutrient losses. The results demonstrate the potential of lignocellulosic biomass-derived fertilizers in promoting resource efficiency and sustainable agriculture. While this research significantly contributes to the existing body of knowledge, further studies on long-term impacts and scalability are recommended for the development of innovative and sustainable agricultural practices.

Innovative approaches for amino acid production via consolidated bioprocessing of agricultural biomass

Agricultural plantations in Indonesia and Malaysia yield substantial waste, necessitating proper disposal to address environmental concerns. Yet, these wastes, rich in starch and lignocellulosic content, offer an opportunity for value-added product development, particularly amino acid production. Traditional methods often rely on costly commercial enzymes to convert biomass into fermentable sugars for amino acid production. An alternative, consolidated bioprocessing, enables the direct conversion of agricultural biomass into amino acids using selected microorganisms. This review provides a comprehensive assessment of the potential of agricultural biomass in Indonesia and Malaysia for amino acid production through consolidated bioprocessing. It explores suitable microorganisms and presents a case study on using Bacillus subtilis ATCC 6051 to produce 9.56 mg/mL of amino acids directly from pineapple plant stems. These findings contribute to the advancement of sustainable amino acid production methods using agricultural biomass especially in Indonesia and Malaysia through consolidated bioprocessing, reducing waste and enhancing environmental sustainability.

Production of mannooligosaccharides from orange peel waste with β-mannanase expressed in Trichosporonoides oedocephalis

A large quantity of orange peel waste (OPW) is generated per year, yet effective biorefinery methods are lacking. In this study, Trichosporonoides oedocephalis ATCC 16958 was employed for hydrolyzing OPW to produce soluble sugars. Glycosyl hydrolases from Paenibacillussp.LLZ1 which can hydrolyze cellulose and hemicellulose were mined and characterized, with the highest β-mannanase activity of 39.1 U/mg at pH 6.0 and 50 ℃. The enzyme was overexpressed in T. oedocephalis and the sugar production was enhanced by 16 %. The accumulated sugar contains 57 % value-added mannooligosaccharides by the hydrolysis of mannans. The process was intensified by a pretreatment combining H2O2 submergence and steam explosion to remove potential inhibitors. The mannooligosaccharides yield of 6.5 g/L was achieved in flask conversion and increased to 9.7 g/L in a 5-L fermenter. This study improved the effectiveness of orange peel waste processing, and provided a hydrolysis-based methodology for the utilization of fruit wastes.

New insights into the sustainable use of soluble straw humic substances for the remediation of multiple heavy metals in contaminated soil

This study addresses the research gap in understanding the differences in straw decomposition and variations in humic substances (HS) extracted from various treatment conditions. The aim is to explore the potential of soluble straw HS in remediating heavy metal pollution in soils. The study characterizes straw decomposition structures using scanning electron microscopy (SEM) and X-ray diffraction (XRD), while employing gel permeation chromatography (GPC) and fluorescence spectroscopy (EEM) to analyze the molecular weight and degree of humification of extracted straw HS. The removal efficiency of HS for heavy metals is assessed, with a focus on aerobic humic substances (AE-HS) showing the highest potential for heavy metal removal. Spectral analysis and mass spectrometry analysis reveal the role of phenolic compounds, carboxylic acids, and aromatic compounds in AE-HS, forming humates or complexes to remove heavy metals from contaminated soil. Notably, the optimized AE-HS achieved the highest removal efficiency of 96.18 %, 82.75 %, 60.43 %, and 41.66 % for cadmium, copper, zinc, and lead, respectively. This study provides new insights into the preparation of straw for use as a heavy metal remover and has implications for the use of straw humic substances in soil remediation.

Assessing the promoting effect of compound microbial agents on flax dew retting: Based on the relationship between metabolites and core genera

In this study, 16S rRNA sequencing and GC-MS (gas chromatography-mass spectrometry) techniques were employed to examine the relationship between bacterial succession and metabolite alterations during the dew retting process of flax. The results indicated that the addition of compound microbial agents may affect the production and transformation of metabolites by re-establishing bacterial communities and promoting the degradation of pectic substances and the release of metabolites, and the best retting effect was achieved under the combined addition (BA). In addition, Chryseobacterium, Bacillus, and Pseudoonas were closely associated with the production of fatty acids and alcohols; the addition of compound microbial agents increased the content of critical metabolites while decreasing the environmental pollutant bis(2-ethylhexyl) phthalate. In summary, the addition of compound microbial agents can positively regulate the retting process of flax, shorten the retting cycle, improve the quality of flax fibre, and reduce the pollution of the environment.

Isolation and Extraction of Monomers from Insoluble Dietary Fiber

Insoluble dietary fiber is a macromolecular polysaccharide aggregate composed of pectin, glycoproteins, lignin, cellulose, and hemicellulose. All agricultural by-products contain significant levels of insoluble dietary fiber. With the recognition of the increasing scarcity of non-renewable energy sources, the conversion of single components of dietary fiber into renewable energy sources and their use has become an ongoing concern. The isolation and extraction of single fractions from insoluble dietary fiber is one of the most important recent research directions. The continuous development of technologies for the separation and extraction of single components is aimed at expanding the use of cellulose, hemicellulose, and lignin for food, industrial, cosmetic, biomedical, and other applications. Here, to expand the use of single components to meet the new needs of future development, separation and extraction methods for single components are summarized, in addition to the prospects of new raw materials in the future.