Bio-based Processes Research Articles

Stable Platform for Mevalonate Bioproduction from CO2.

Stable production of value-added products using a microbial chassis is pivotal for determining the industrial suitability of the engineered biocatalyst. Microbial cells often lose the multicopy expression plasmids during long-term cultivations. Owing to the advantages related to titers, yields, and productivities when using a multicopy expression system compared with genomic integrations, plasmid stability is essential for industrially relevant biobased processes. Cupriavidus necator H16, a facultative chemolithoautotrophic bacterium, has been successfully engineered to convert inorganic carbon obtained from CO2 fixation into value-added products. The application of this unique capability in the biotech industry has been hindered by C. necator H16 inability to stably maintain multicopy plasmids. In this study, we designed and tested plasmid addiction systems based on the complementation of essential genes. Among these, implementation of a plasmid addiction tool based on the complementation of mutants lacking RubisCO, which is essential for CO2 fixation, successfully stabilized a multicopy plasmid. Expressing the mevalonate pathway operon (MvaES) using this addiction system resulted in the production of ∼10 g/L mevalonate with carbon yields of ∼25%. The mevalonate titers and yields obtained here using CO2 are the highest achieved to date for the production of C6 compounds from C1 feedstocks.

Engineering new-to-nature biochemical conversions by combining fermentative metabolism with respiratory modules

Anaerobic microbial fermentations provide high product yields and are a cornerstone of industrial bio-based processes. However, the need for redox balancing limits the array of fermentable substrate-product combinations. To overcome this limitation, here we design an aerobic fermentative metabolism that allows the introduction of selected respiratory modules. These can use oxygen to re-balance otherwise unbalanced fermentations, hence achieving controlled respiro-fermentative growth. Following this design, we engineer and characterize an obligate fermentative Escherichia coli strain that aerobically ferments glucose to stoichiometric amounts of lactate. We then re-integrate the quinone-dependent glycerol 3-phosphate dehydrogenase and demonstrate glycerol fermentation to lactate while selectively transferring the surplus of electrons to the respiratory chain. To showcase the potential of this fermentation mode, we direct fermentative flux from glycerol towards isobutanol production. In summary, our design permits using oxygen to selectively re-balance fermentations. This concept is an advance freeing highly efficient microbial fermentation from the limitations imposed by traditional redox balancing.

Microbial production of an aromatic homopolyester

We report the development of a metabolically engineered bacterium for the fermentative production of polyesters containing aromatic side chains, serving as sustainable alternatives to petroleum-based plastics. A metabolic pathway was constructed in an Escherichia coli strain to produce poly[d-phenyllactate(PhLA)], followed by three strategies to enhance polymer production. First, polyhydroxyalkanoate (PHA) granule-associated proteins (phasins) were introduced to increase the polymer accumulation. Next, metabolic engineering was performed to redirect the metabolic flux toward PhLA. Furthermore, PHA synthase was engineered based on in silico simulation results to enhance the polymerization of PhLA. The final strain was capable of producing 12.3 g/l of poly(PhLA), marking it the first bio-based process for producing an aromatic homopolyester. Additional heterologous gene introductions led to the high level production of poly(3-hydroxybutyrate-co-11.7 mol% PhLA) copolymer (61.4 g/l). The strategies described here will be useful for the bio-based production of aromatic polyesters from renewable resources.

Boosting the transition to biorefineries in compliance with sustainability and circularity criteria

In the transition towards climate neutrality, biorefinery models are considered promising alternatives to processes based on fossil fuels and non-renewable materials. This consideration is attributed to the reduction of dependence on non-renewable systems, in line with greener and lower impact technological strategies. However, they imply a profound transformation of the production system, as the variable and stochastic nature of certain renewable sources makes it necessary to have various tools to provide flexibility and optimize the system. Their market penetration is currently limited by their level of development and the regulatory and financial support to implement the paradigm shift. Traditional linear production is still more economically viable compared to circular production models, based on efficiency parameters achieved by years of manufacturing experience. To reverse this trend, it is necessary to leverage its benefits through the use of appropriate assessment tools, as these are the ones that could drive the move towards biorefineries. This is the focus of this research report, which reviews various evaluation methodologies and indicators to effectively evaluate bio-based process schemes. Life Cycle Assessment (LCA), Product Environmental Footprint (PEF), Green Chemistry Principles (GCP), certification scheme requirements and Circular Economy Action Plans are reviewed and integrated into a precise assessment framework. To determine their effectiveness, three biorefinery models were evaluated: valorization of apple vinasses, grape must and chickpea peel. Through the combined analysis of bio-based scenarios, it has been possible to identify their benefits, bottlenecks and limitations, and to validate a comprehensive assessment framework that allows an accurate, effective and conscious analysis of bio-based models, promoting their development and market penetration.

The circular bioeconomy: a driver for system integration

BackgroundHuman and earth system modeling, traditionally centered on the interplay between the energy system and the atmosphere, are facing a paradigm shift. The Intergovernmental Panel on Climate Change’s mandate for comprehensive, cross-sectoral climate action emphasizes avoiding the vulnerabilities of narrow sectoral approaches. Our study explores the circular bioeconomy, highlighting the intricate interconnections among agriculture, forestry, aquaculture, technological advancements, and ecological recycling. Collectively, these sectors play a pivotal role in supplying essential resources to meet the food, material, and energy needs of a growing global population. We pose the pertinent question of what it takes to integrate these multifaceted sectors into a new era of holistic systems thinking and planning.ResultsThe foundation for discussion is provided by a novel graphical representation encompassing statistical data on food, materials, energy flows, and circularity. This representation aids in constructing an inventory of technological advancements and climate actions that have the potential to significantly reshape the structure and scale of the economic metabolism in the coming decades. In this context, the three dominant mega-trends—population dynamics, economic developments, and the climate crisis—compel us to address the potential consequences of the identified actions, all of which fall under the four categories of substitution, efficiency, sufficiency, and reliability measures. Substitution and efficiency measures currently dominate systems modeling. Including novel bio-based processes and circularity aspects might require only expanded system boundaries. Conversely, paradigm shifts in systems engineering are expected to center on sufficiency and reliability actions. Effectively assessing the impact of sufficiency measures will necessitate substantial progress in inter- and transdisciplinary collaboration, primarily due to their non-technological nature. In addition, placing emphasis on modeling the reliability and resilience of transformation pathways represents a distinct and emerging frontier that highlights the significance of an integrated network of networks.ConclusionsExisting and emerging circular bioeconomy practices can serve as prime examples of system integration. These practices facilitate the interconnection of complex biomass supply chain networks with other networks encompassing feedstock-independent renewable power, hydrogen, CO2, water, and other biotic, abiotic, and intangible resources. Elevating the prominence of these connectors will empower policymakers to steer the amplification of synergies and mitigation of tradeoffs among systems, sectors, and goals.

Influence of silane-modified palm oil as a green processing oil in silica-reinforced SBR/BR compounds for tire tread applications

This study focuses on the usage of silane-modified palm oil (Si-m-PO) to replace petroleum-based processing oils, i.e., distillate aromatic extract (DAE) and treated distillate aromatic extract (TDAE), in silica-reinforced styrene butadiene rubber/butadiene rubber (SBR/BR) compounds for green tire tread products. The preparation of a novel processing oil based on Si-m-PO was successful on the laboratory scale, as verified by nuclear magnetic resonance, where the grafting efficiency of silane in oil molecules was 58%. Among the different types of processing oils, the presence of Si-m-PO in the compounds resulted in lower filler-filler interactions than the ones with TDAE and unmodified PO but higher than DAE. The Si-m-PO showed an effective reduction in filler–filler interaction compared to unmodified PO, possibly because the Si-m-PO could cover silica surfaces via silane linkage, leading to hydrophobicity of silica surfaces. Overall, the compounds containing Si-m-PO represented higher mechanical properties than the other oils. Furthermore, the Si-m-PO provided the same level concerning rolling resistance and enhanced wet traction, when compared to unmodified PO. Therefore, Si-m-PO can be applied as a biobased processing oil in tire tread applications.

Combined bio-methanol and power production from bio-oil: Proposing a clean bio-process through waste heat recovery and environmental optimization

Traditional methanol production from natural gas is well-studied, but there is a lack of research on environmentally optimizing bio-based methanol production. This study focuses on optimizing the combined production of bio-methanol and power from bio-oil using a comprehensive bio-process model. The research includes a novel framework for environmental, technical, and economic optimization of bio-oil to methanol and power to determine the most eco-friendly and cost-effective approach. An organic Rankine cycle (ORC) is also integrated for waste heat recovery. The results of this study revealed that the bio-based process with ORC showed a 22.6 % reduction in global warming potential impact (GWP) per kilogram of methanol, compared to the bio-based process without ORC. Also, by implementing the most environmentally friendly process, GWP will be reduced by 70.6 % per kg methanol compared to base sub-optimal operation. The results showed that for the process with the addition of ORC, after performing multi-objective optimization, under the optimal conditions, the economic annual rate of return increased from 19.6 % to 34.7 %. Finally, it was revealed that if the considered technology is commercialized, for every percentage of the methanol market it gains, it will contribute to 2.176 million tons CO2-eq/year less emissions.

Composite ultrathin membranes for clarification and primary recovery of biobased itaconic acid from fermentation broths

Itaconic acid is a biobased organic acid with clear potential to become a relevant renewable building-block chemical. However, to compete with petrochemical processes, the production cost of biobased processes, particularly the downstream processing contribution, needs to be reduced. In this work, composite membranes comprising ultrathin films of crosslinked poly[(o-cresyl glycidyl ether)-co-formaldehyde] and branched polyethyleneimine on mixed cellulose ester supports were developed for application in the primary recovery of itaconic acid from fermentation broths. In contrast to commercial and literature-reported counterparts, these membranes exhibit low itaconic acid rejections over a wide range of pH, ionic strength, organic acid concentration and operating pressure. Moreover, these membranes can efficiently recover itaconic acid from clarified fermentation broth as well as unclarified fermentation broth of Pichia pastoris cultivations, with average rejections below 15 % recorded over 8 h of operation. Lastly, the performance of these membranes was compared to literature-reported strategies for primary recovery of biobased organic acids. The efficient recovery of itaconic acid from unclarified fermentation broth opens the possibility to perform clarification and primary recovery simultaneously, thus simplifying the downstream processing of biobased itaconic acid considerably.

Enhancing the tire performances of truck tire tread based on rubber compounds containing biobased processing oil by adjusting sulfur contents

The mechanical properties of the rubber compounds such as modulus and tensile strength are very important to rubber products especially for tire applications. However, the presence of palm oil (PO) as a biobased processing oil in eco-friendly truck tire tread compounds encounters the low mechanical properties because PO molecules can consume sulfur as a curing agent. Therefore, this study focuses on incorporation of sulfur in varying contents on the properties of rubber compounds. The PO-added natural rubber compounds with different sulfur contents of 2.50, 2.75, and 3.00 parts per hundred rubber (phr) were prepared by taking the use of distillated aromatic extract (DAE) in natural rubber compound with 2.50 phr sulfur as a reference. The levels of crosslinking of the PO-added natural rubber compounds increased as the sulfur content increased, resulting in improvement in mechanical properties. Results showed that an additional incorporation of 0.25 phr sulfur content led to superior mechanical properties. Furthermore, PO improved the abrasion resistance by 38%, reduced heat buildup by 17%, and lowered tan δ at 60°C by 21%, when compared to the compound as a reference. Based on the results, the additional incorporation of sulfur not only improved the mechanical properties, but also enhanced tire performances especially low rolling resistance as reflected by energy-saving tires. Thus, PO can be an alternative to DAE in the natural rubber compounds for the application of truck tire treads when the additional incorporation of sulfur was applied.

Optimized Bioleaching Pre-treatment of UG-2 PGM Flotation Concentrate Using Design of Experiments

The depletion of the Merensky ore has led the South African platinum industry into largely mining and processing Upper Group Two (UG-2) ore for the extraction of Platinum Group Metals (PGMs). However, the processing of the UG-2 material is not fully amenable to the conventional pyrometallurgical route due to the high chrome content. Therefore, in this study, a bio-based process for base metal extraction from UG-2 flotation concentrates was investigated. This study represents only part of the work done in a broader investigation to develop a completely biological two-stage process for the extraction of base metals and PGEs. In this paper, only the first stage of the process is presented. This study evaluated a mixture of indigenous thermoacidophile archaebacteria namely, Acidianus brierleyi, Sulfolobus sp., and Metallosphaera sedula. A statistical Design of Experiments (DOE) was used for finding optimal conditions. Factors investigated included particle size, pH, pulp density, inoculum dosage, and temperature. Optimal extraction efficiencies of 92% for Co, 97% for Cu, and 99% for Ni were predicted at correlation coefficients of 92.5%, 93.2%, and 88.0%, respectively, thus, verifying the fitness of the model. Optimal base metal extractions obtained were 99.3% for Co, 90.1% for Cu, 41.58% for Fe, and 99.5% for Ni. The results showed a substantial extraction of base metals from UG-2 PGM flotation concentrate suggesting a potentially feasible option for industrial bioprocessing of PGM concentrates. To the best of the authors’ knowledge, this is the first report on bioleaching of base metals from UG-2 flotation concentrates.Graphical

Current state of predictive activity models when applied to cyclic bio-compounds and biodiesel related mixtures

The rise in greenhouse gas emissions makes the research and development of renewable energy sources a crucial area, with a particular emphasis on biofuels derived from biomass. In this context, design, simulation, an optimization of such bio-based process will also pose many challenges for thermodynamic models. Classical equations of state usually fail to describe these systems and there is not enough experimental data to correlate binary parameters even for group contribution models like UNIFAC. In this case, COSMO-based models become an interesting alternative, since they do not depend directly on experimental data. Even for the well-know biodiesel production there are intermediaries and byproducts showing phase equilibria that are difficult to predict. The UNIFAC (Do) and COSMO-SAC-HB2 variant were used to predict phase equilibria for mixtures related to bio-compounds. For COSMO-SAC, the first step was the revision and extension of the sigma-LVPP public database for the related molecules. For the modified UNIFAC, literature parameters were considered. Vapor-liquid, infinite dilution activity coefficient, liquid-liquid and excess enthalpy data were collected, with a total of 135 systems were investigated. The COSMO-SAC-HB2 yielded satisfactory deviation results in equilibrium of mixtures involving biocompounds, water, and alcohols. UNIFAC (Do) demonstrated satisfactory results in mixtures involving biocompounds and esters, hydrocarbons and alcohols.

Bioethanol separation by a new pass-through distillation process

Distillation is the most used separation technology at industrial-scale, but using distillation in bio-based processes (e.g. fermentation processes to produce bioethanol) is quite challenging when mild temperatures are needed to keep the microbes alive. Vacuum distillation can be used to perform evaporation at low temperatures, but setting a low distillation pressure fixes also the condensation temperature to very low values that may require expensive refrigeration.Pass-through distillation (PTD) is an emerging hybrid separation technology that effectively combines distillation with absorption in a sorption-assisted distillation process that decouples the evaporation and condensation steps. This is achieved by inserting between the evaporation and condensation steps an absorption-desorption loop that passes through the component to be separated and allows the use of different pressures and types of heating and cooling utilities.This paper is the first to present the process design and rigorous simulation (implemented in Aspen Plus) of a new pass-through distillation process for bioethanol (∼100 ktonne/y plant capacity), proving its effectiveness in concurrent alcohol recovery and fermentation (CARAF). Combining PTD with heat pumps leads to low recovery costs of 0.122 $/kgEtOH and energy requirements of only 1.723 kWthh/kgEtOH. Alternatively, combining PTD with multi-effect distillation resulted in 0.131 $/kgEtOH recovery costs and 1.834 kWthh/kgEtOH energy intensity.

Enhancing Anaerobic Digestion with an UASB Reactor of the Winery Wastewater for Producing Volatile Fatty Acid Effluent Enriched in Caproic Acid

The production of Volatile Fatty Acids (VFAs) from wastewater holds significant importance in the context of biorefinery concepts due to their potential as valuable precursors for various bio-based processes. Therefore, the primary objective of this research is to investigate the fermentation of Winery Wastewater (WW) in an Upflow Anaerobic Sludge Blanket (UASB) reactor to generate VFAs, with particular emphasis on Caproic Acid (HCa) production and the dynamics of the microbiota, under varying Hydraulic Retention Time (HRT) periods (8, 5, and 2.5 h). The change from an 8 h to a 5 h HRT period resulted in an approximately 20% increase in total VFA production. However, when the HRT was further reduced to 2.5 h, total VFA production decreased by approximately 50%. Concerning the specific production of HCa, expressed in grams of Chemical Oxygen Demand (gCOD), the maximum yield was observed at around 0.9 gCOD/L for a 5-h HRT. Microbial population analysis revealed that Eubacteria outnumbered Archaea across all HRTs. Population dynamics analysis indicated that the Firmicutes Phylum was predominant in all cases. Within this phylum, bacteria such as Clostridium kluyveri and Clostridium sp., known for their ability to produce HCa, were identified. Based on the results obtained, the application of the UASB reactor for WW treatment, within the biorefinery framework, has the potential to provide a practical alternative for HCa production when operated with a 5 h HRT.

Design, Evaluation, and Implementation of Synthetic Isopentyldiol Pathways in Escherichia coli.

Isopentyldiol (IPDO) is an important raw material in the cosmetic industry. So far, IPDO is exclusively produced through chemical synthesis. Growing interest in natural personal care products has inspired the quest to develop a biobased process. We previously reported a biosynthetic route that produces IPDO via extending the leucine catabolism (route A), the efficiency of which, however, is not satisfactory. To address this issue, we computationally designed a novel non-natural IPDO synthesis pathway (route B) using RetroPath RL, the state-of-the-art tool for bioretrosynthesis based on artificial intelligence methods. We compared this new pathway with route A and two other intuitively designed routes for IPDO biosynthesis from various perspectives. Route B, which exhibits the highest thermodynamic driving force, least non-native reaction steps, and lowest energy requirements, appeared to hold the greatest potential for IPDO production. All three newly designed routes were then implemented in the Escherichia coli BL21(DE3) strain. Results show that the computationally designed route B can produce 2.2 mg/L IPDO from glucose but no IPDO production from routes C and D. These results highlight the importance and usefulness of in silico design and comprehensive evaluation of the potential efficiencies of candidate pathways in constructing novel non-natural pathways for the production of biochemicals.

Early stages of X-ray induced molecular unit modifications in poly(lactic acid)

Exposure of polymers to ionizing radiation and high-energy particle beams is involved in many processes – from food sterilization to radiotherapy protocols. The resulting effects, at the final stages, determine the functional, structural, and morphological alteration of the material. However, the processes responsible for cumulative chain scission, crosslinking, and reactions with the environment are often difficult to disentangle as a sequence of elementary events. Here we report a spectroscopic study – by attenuated-total reflection Fourier transform infrared spectroscopy and powder x-ray diffraction measurements, together with differential scanning calorimetry and thermogravimetric analyses – that sheds light on the very initial stages of the mechanisms involved in radiation-induced modifications of poly(lactic acid) (PLA). The results, collected on samples from biobased processes and exposed to low x-ray doses in the range of 100–103Gy after different thermal treatments, show spectroscopic evidence of the emergence of molecular unit perturbations – mainly related to methyl and carbonyl groups with the formation of C=C double bonds – with a clear-cut dependence on the polymer conformation. Understanding the mechanisms involved and the role of crystallinity provides information potentially useful for the development of PLA with a suitable radiation hardness for applications in radiotherapy.

Perspective on opportunities of bio-based processing oil to rubber industry: a short review

Perspective on opportunities of bio-based processing oil to rubber industry: a short review

Life cycle assessment of an integrated xylitol biorefinery with value-added co-products

PurposeThis manuscript comprises a detailed life cycle assessment of an integrated xylitol biorefinery with value-added co-products. The biorefinery utilizes wheat straw as lignocellulosic feedstock and employs bio-based processes to produce xylitol as the main product and succinic acid as a co-product. The biorefinery was conceptually designed in an optimization-based framework and assessed through a techno-economic analysis published in the authors’ prior publications.MethodsThe goal is to determine the environmental impacts of the xylitol biorefinery and to compare the effects of bio-based production in the biorefinery to the current chemical production processes of xylitol. The scope is set as cradle-to-gate to allow a direct comparison of the chemical processes. The presented life cycle assessment was performed according to the standardized ISO procedure.ResultsThe reference unit is related to the feedstock as multiple products are produced, and an economic allocation is chosen. The life cycle inventory is based on secondary data from process simulations stemming from earlier published work. The impact assessment is performed with the ReCiPe 2016 Midpoint H V1.05 method and the IMPACT2002 + method since the available data of the life cycle assessment for the chemical processes was obtained with the latter. The characterization of the impacts shows high impacts for the terrestrial, marine, and human carcinogenic toxicity impact categories and a comparatively low impact on global warming.ConclusionsThe results are interpreted and assessed with an additional sensitivity analysis. Furthermore, the results are compared with the two chemical production processes. The comparison shows lower impacts of the xylitol biorefinery compared to the standard chemical production process but slightly higher impacts compared to the proprietary production process of DuPont, which employs a high level of process integration. These results are further discussed and contextualized.

From enzyme to cell-factory: Economic and environmental assessment of biobased pathways to unlock the potential of long-haul transportation biofuels

The transportation sector significantly contributes to greenhouse gas emissions due to its reliance on fossil fuels. Biofuels offer a low-carbon alternative, particularly for long-haul transportation. Although few biosynthetic pathways reached technological maturity with commercial plants, recent literature shows a variety of laboratory-scale progresses targeting these biofuels. Early-stage sustainability assessments can help identify opportunities for metabolic engineering and process improvements toward more sustainable routes. This study evaluated the technical, economic, and environmental aspects of producing drop-in biofuels from sugarcane and soybean oil, considering fermentative and enzymatic processes. The results showed that sugarcane-based scenarios presented a better prospect and that integrating steps within microorganisms’ metabolism in a cell factory concept had advantages over the cell-free enzymatic process. Biobased pathways, however, still require improvements to be competitive with catalytic-based alternatives. Recommendations were made to guide microorganism engineering, focusing on factors that restrain economic and environmental feasibility (e.g., inputs use). As a result, the improved biobased process could provide a hydrocarbon-based fuel with a minimum selling price (US$ 21.2 GJ−1) compatible with market prices and carbon intensity (25.1 gCO2eq MJ−1) similar to that from sugarcane ethanol, representing over 70 % reduction in greenhouse gas (GHG) emissions compared to fossil fuels.

Purification and biochemical characterization of SM14est, a PET-hydrolyzing enzyme from the marine sponge-derived Streptomyces sp. SM14.

The successful enzymatic degradation of polyester substrates has fueled worldwide investigation into the treatment of plastic waste using bio-based processes. Within this realm, marine-associated microorganisms have emerged as a promising source of polyester-degrading enzymes. In this work, we describe the hydrolysis of the synthetic polymer PET by SM14est, a polyesterase which was previously identified from Streptomyces sp. SM14, an isolate of the marine sponge Haliclona simulans. The PET hydrolase activity of purified SM14est was assessed using a suspension-based assay and subsequent analysis of reaction products by UV-spectrophotometry and RP-HPLC. SM14est displayed a preference for high salt conditions, with activity significantly increasing at sodium chloride concentrations from 100 mM up to 1,000 mM. The initial rate of PET hydrolysis by SM14est was determined to be 0.004 s-1 at 45°C, which was increased by 5-fold to 0.02 s-1 upon addition of 500 mM sodium chloride. Sequence alignment and structural comparison with known PET hydrolases, including the marine halophile PET6, and the highly efficient, thermophilic PHL7, revealed conserved features of interest. Based on this work, SM14est emerges as a useful enzyme that is more similar to key players in the area of PET hydrolysis, like PHL7 and IsPETase, than it is to its marine counterparts. Salt-tolerant polyesterases such as SM14est are potentially valuable in the biological degradation of plastic particles that readily contaminate marine ecosystems and industrial wastewaters.

Integrated Biobased Processes for Nanocellulose Preparation from Rice Straw Cellulose

High-potential nanomaterials were derived from rice straw using the integrated biobased processes of enzymatic hydrolysis with green organic acid hydrolysis assisted with ultrasonication pretreatment. The optimization condition of nanocellulose preparation by enzymatic hydrolysis via central composite design (CCD) achieved a maximum nanocellulose content of 32.37 ± 0.47% using a cellulase concentration of 107.06 U/mL and 0.13% (w/w) of rice straw cellulose. The ultrasonication-assisted pretreatment prior to enzymatic hydrolysis improved nanocellulose preparation to 52.28 ± 1.55%. Integration with oxalic acid hydrolysis increased the nanocellulose content to 64.99 ± 0.16%. Granular nanocellulose was obtained and consisted of a 105–825 nm nanosize with a zeta potential value of −34.5 mV, and nanocellulose suspension showed high stability without aggregation. In addition, the remaining rice straw cellulose after oxalic acid was microcrystalline nanocellulose. All prepared nanocellulose represented a functional group as original cellulose but had a low crystallinity index (CrI) of 15.68% that could be classified as amorphous nanocellulose. Based on their characteristics, all nanocellose could be further applied in food, cosmetics, and pharmaceuticals. Moreover, the results indicated that the rice straw could be an alternative non-edible cellulose source for preparing potential nanocellulose via a controlled hydrolysis process.