Sustainable Bio-based Products Research Articles

Intensification of bioprocesses – definition, examples, challenges and future directions

Abstract Strategies to reduce cost and emission profiles are becoming increasingly important for the development of affordable and sustainable bio-based production. The overall objective of process intensification in different industries is to achieve substantial benefits in terms of cost, product concentration and quality, while eliminating waste and improving process safety. Intensification of bioprocesses could be a valuable tool for enhancing the efficiency and reducing resource consumption in bioproduction. In general, bioprocess intensification is defined as an increase in bioproduct output relative to cell concentration, time, reactor volume or cost. This brief overview provides a definition of process intensification in biotechnology, presents several general and specific examples, and addresses some of the current challenges.

Microbial Cell Factories: Biodiversity, Pathway Construction, Robustness, and Industrial Applicability

The microbial biosynthesis of proteins, primary metabolites, and chemicals is gaining extraordinary momentum and is presently viewed as an advancing approach in the industrial research sector. Increased threats to the environment and the possibility of declining petroleum assets have switched the spotlight to microbial cell factories (MCFs). Aside from possessing various advantages over chemical synthesis, such as less toxicity, cheaper methodologies, and an environmentally benign nature, microbes can be cultivated in fermenters, resulting in an effective bioprocessing approach in terms of industrial relevance. As the overwhelming majority of biodiversity is microbial, this review first highlights the microbial biodiversity of industrially vital microorganisms. Then, the paper delineates the production pathways for generating valuable bioproducts via microbial workhorses. Many host cells synthesize bio-compounds as a part of their natural mechanism; however, several techniques have also been developed to attain the desired end product from non-native microbes with selected properties. The microbial biosynthetic pathways can be categorized as native-existing pathways, heterologous pathways, and artificial de novo pathways. Systems metabolic engineering, which integrates metabolic engineering with evolutionary engineering, synthetic biology, and systems biology, has further revolutionized the field of engineering robust phenotypes. The employment of these strategies improves the performance of the strain, eventually achieving high titer and productivity rates of bio-chemicals. Modern trends and tools for exploiting native pathways and designing non-native-created pathways are also briefly discussed in this paper. Finally, the review discusses the use of microbial workhorses for producing a myriad of materials and chemicals, including carboxylic acids, amino acids, plant natural products (PNPs), carotenoids, flavors, and fragrances, unveiling the efficacy of utilizing microbial species to generate sustainable bio-based products.

Comparative study of the structure and mechanical properties of starch aerogels fabricated from air-classified and isolated pulse starches

Significant amounts of starch and protein are generated as co-products during fractionation of pulse seeds. While pulse proteins (PP) have garnered a lot of interest in numerous applications, little attention is shown to pulse starch (PS). The creation of novel materials such as bioplastics could revolutionize the use of pulse starches. In this study, we investigated the prospects of air-classified and isolated pea, lentil, and faba bean starches as a precursor for fabricating pulse starch bioaerogels (PSBs) via freeze-drying technique. The results evidenced ultra-low densities (<0.1 m2/g), mesopore sizes (2−50 μm), high porosities (∼99 %), low surface areas (SBET = ∼4−18 m2/g) for all the aerogels. The adsorption isotherm showed typical Type II and III profiles, while the thermogravimetric analysis showed more weight loss (74.39−78.12 %) in aerogels mostly developed from isolated starches. Microstructural studies showed a unique distribution of pores within the developed aerogels. FTIR and XPS studies confirmed the presence of an amide (I, II, III) at different absorption bands range (∼1600–1200 cm−1) and functional groups (carboxylic group and the amide group), respectively. All the PSBs became stiffer with a corresponding increase in load, and a reversible deformation in the linear region was identified at <5 % strain. Comparatively, saturated PSBs from air-classified starch at a relative humidity of 95 % showed a drastic reduction in their compressive moduli (CM), while PSBs from isolated starch experienced markedly high CM. Moisture saturation was achieved at 72 h for all the samples. This study provides crucial information that could spark a keen interest in the use of non-conventional starch for the creation of novel and sustainable biobased products with expanded applications.

Metabolic engineering of Escherichia coli for the efficient production of 5-hydroxyvaleric acid

There is increasing industrial demand for five-carbon platform chemicals, particularly 5-hydroxyvaleric acid (5-HV), a widely used building block for the synthesis of polyesters and polyurethanes. Here, we developed an efficient 5-HV microbial producer by systems metabolic engineering of Escherichia coli W3110. To derive 5-HV, Pseudomonas putidal-lysine monooxygenase (davB) and 5-aminovaleramide amidohydrolase (davA), E. coli 4-aminobutyrate aminotransferase (gabT), and different aldehyde reductase genes were introduced to E. coli W3110 to convert l-lysine hydrochloride to the target product. Three aldehyde reductases, including YajO from P. putida and YahK and YqhD from E. coli, were examined, revealing that the overexpression of aldehyde reductases was critical for 5-HV production and YajO was first reported for efficient production of 5-HV. The E. coli 5-aminovalerate exporter encoded by gabP and E. coli lysine-specific permease encoded by lysP were expressed to further enhance 5-HV production. In addition, a hok/sok toxin/antitoxin system based on the E. coli XL1-Blue genome was inserted to the dual-vector system to decrease plasmid loss. Finally, 5.59 g/L of 5-HV with a yield of 0.96 mol/mol (5-HV/l-lysine hydrochloride) by shake flask cultivation of the engineered E. coli W3110 and 35.6 g/L of 5-HV with a yield of 0.92 mol/mol (5-HV/l-lysine hydrochloride) by fed fermentation were achieved respectively. The developed metabolic engineering strategies provide a basis for the efficient and sustainable bio-based production of 5-HV.

An improved integrative GFP-based vector for genetic engineering of Parageobacillus thermoglucosidasius facilitates the identification of a key sporulation regulator

Parageobacillus thermoglucosidasius is a thermophilic Gram-positive bacterium, which is a promising host organism for sustainable bio-based production processes. However, to take full advantage of the potential of P. thermoglucosidasius, more efficient tools for genetic engineering are required. The present study describes an improved shuttle vector, which speeds up recombination-based genomic modification by incorporating a thermostable sfGFP variant into the vector backbone. This additional selection marker allows for easier identification of recombinants, thereby removing the need for several culturing steps. The novel GFP-based shuttle is therefore capable of facilitating faster metabolic engineering of P. thermoglucosidasius through genomic deletion, integration, or exchange. To demonstrate the efficiency of the new system, the GFP-based vector was utilised for deletion of the spo0A gene in P. thermoglucosidasius DSM2542. This gene is known to be a key regulator of sporulation in Bacillus subtilis, and it was therefore hypothesised that the deletion of spo0A in P. thermoglucosiadius would produce an analogous sporulation-inhibited phenotype. Subsequent analyses of cell morphology and culture heat resistance suggests that the P. thermoglucosidasius ∆spo0A strain is sporulation-deficient. This strain may be an excellent starting point for future cell factory engineering of P. thermoglucosidasius, as the formation of endospores is normally not a desired trait in large-scale production.

Efficient bio-production of glutaric acid by a metabolically engineered Escherichia coli LQ-1 based on a novel nitrogen source feeding strategy.

As an important five-carbon platform chemical to synthesize polyesters and polyamides, glutaric acid is widely used in numerous biochemical fields such as consumer goods, textile, and footwear industries. However, the application of glutaric acid is limited by the low yield of its bio-production. In this study, a metabolically engineered Escherichia coli LQ-1 based on 5-aminovalerate (AMV) pathway was used for glutaric acid fed-batch fermentation. Given the significance of nitrogen source in the bio-production of glutaric acid by AMV pathway, a novel nitrogen source feeding strategy feedbacked by real-time physiological parameters was proposed after evaluating the effects of nitrogen source feeding (such as ammonia and ammonium sulfate) on glutaric acid bio-production. Under the proposed nitrogen source feeding strategy, a significantly improved glutaric acid production of 53.7g L-1 was achieved in a 30 L fed-batch fermentation by the metabolically engineered E. coli LQ-1, which was an improvement of 52.1% over pre-optimization. Additionally, a higher conversion rate of 0.64molmol-1 (glutaric acid/glucose) was obtained compared with the previously reported bio-production of glutaric acid with E. coli. These results indicated that the nitrogen source feeding strategy proposed in this study will be useful for achieving the efficient and sustainable bio-based production of glutaric acid.

Enzymatic synthesis of\xa0kraft\xa0lignin-acrylate\xa0copolymers using\xa0an alkaline tolerant\xa0laccase

Softwood kraft lignin is a major bioresource relevant to the production of sustainable bio-based products. Continued challenges to lignin valorization, however, include poor solubility in organic solvents and in aqueous solutions at neutral pH. Herein, an alkaline tolerant laccase was used to graft acrylate functionalities onto softwood kraft lignin, which is expected to enhance the reactivity of lignin with isocyanate when producing bio-based polyurethanes. Proton nuclear magnetic resonance, Fourier-transform infrared spectroscopy, and high-performance liquid chromatography were used to confirm successful grafting of the acrylate monomer onto lignin and verify the importance of including tert-butyl hydroperoxide as an initiator in the grafting reaction. Laccase-mediated grafting of softwood kraft lignin under alkaline conditions produced lignin products with approximately 30% higher hydroxyl value and higher reactivity toward isocyanate. The reported enzymatic and aqueous process presents an opportunity for the sustainable valorization of softwood kraft lignin.Key points• Softwood kraft lignin displayed high phenolic hydroxyl content, polydispersity index and average molecular weight• Grafting hydroxyethyl acrylate (HEA) monomer onto kraft lignin by laccase was successful at 60 °C and alkaline conditions• Lignin-HEA grafted copolymer showed an increase in total OH value and an increase in average molecular weight

The use of treatment wetlands plants for protein and cellulose valorization in biorefinery platform

Different wetland plants were evaluated regarding their potential to be used in further green biorefining platforms to produce soluble protein and cellulose-textile fibers. The results show a higher protein content in the plants grown in treatment wetland conditions, compared with the same species grown in natural conditions, and diverse effect on the content of cellulose, hemicellulose, and lignin, depending on the plant species, more than the growing environment. The TW biomass did not represent a risk regarding accumulation of heavy metals, named Pb, Cd, and Cr, since the studied plants did not present it in their tissues, neither in the roots nor in the leaves. The results regarding cellulose quality of the TW plants showed positive results, having values of molar mass distributions and degrees of polymerization that suggest a suitability to be considered for cellulose-fiber textiles studies. This is one of the first approaches, in the TW field, to establish a new criterion for selecting plant species to be planted in the system, aiming at recovering resources and use them as inputs for biorefineries and sustainable biobased products.

Holistic approach in the evaluation of the sustainability of bio-based products: An Integrated Assessment Tool

The capacity to demonstrate the sustainability of bio-based products is crucial for promoting the full deployment of a circular bio-based economy, and for boosting new products’ market uptake. Hence, there is a growing need to deliver methodological guidance to companies on assessing the sustainability of their innovative and claimed sustainable bio-based products. In this regards, the present article proposes a tool for assessing the sustainability of bio-based products, addressing the most relevant sustainability aspects (i.e. environmental, social, economic and circular) from a life cycle perspective. The proposed integrated assessment tool (IAT) is the result of a transdisciplinary process involving contributions from both industry and academia. To this end, the research involved numerous repeat interactions with practitioners and researchers to guide the selection of relevant areas of sustainability protection and related indicators and metrics, for ultimate inclusion in the tool. Multi-stakeholder workshops, webinars and expert interviews were also employed in the development of the tool´s functional elements (i.e. data collection, scoring, communication). The resulting tool consists of 48 sustainability indicators with proposed metrics based on existing standards, methodologies and best practices in sustainability assessment. The tool scoring system allows users to compare the performance of their bio-based product to an “ideal”. A key finding of the research is that, to produce a complete and reliable sustainability assessment, effective collaboration between economic operators along the bio-based value chain is needed. Furthermore, overall sustainability performance, particularly with respect to the life cycle assessment indicators, are heavily influenced by the type of biomass and related agricultural practices. It is therefore recommended to employ the tool on a case by case basis, maximizing the use of primary data.

Sustainable Circular Bioeconomy—Feasibility of Recycled Nutrients for Biomass Production within a Pulp and Paper Integration in Indonesia, Southeast Asia

Sustainable biomass production based on efficient carbon and nutrient recycling is crucial in materially efficient, sustainable biobased production. A circular bioeconomy model of the replacement of mineral fertilizers with recycled nutrients from pulp and paper mill sludge is tested here within a hypothetical case from Indonesia, Southeast Asia. First, the financial feasibility of the use of recycled nutrients originating from pulp and paper processes was analyzed in fast-growing pulpwood production. Secondly, the comprehensive social and environmental benefits of the practice were analyzed through qualitative sustainability analysis. The availability of the basic material of all required parameters referring to Indonesia limited the analysis period to be from 1996 to 2013. The establishment costs of a pulpwood plantation were adjusted according to a reference study, while the other data were compiled from various sources. The financial profitability of the circular model was analysed by using two indicators, net present value (NPV) and internal rate on return (IRR). The application of sludge-based recycled nutrients slightly increased the establishment costs in some circumstances but had no direct impact on the financial profitability, as the financial profitability was not sensitive to the establishment costs. The results showed that the financial profitability of biomass production is not sensitive to the plantation establishment and management costs. The profitability depends on the mean annual increment and product price. The qualitative analysis showed a holistic value of the practice that goes beyond the direct benefits. The use of sludge-based recycled nutrients in the production of pulpwood closed the economic loop, which is illustrative of the circular bioeconomy within the integrated pulp and paper sector including the raw material source, forest plantation.

The Design-Build-Test-Learn cycle for metabolic engineering of Streptomycetes.

Streptomycetes are producers of a wide range of specialized metabolites of great medicinal and industrial importance, such as antibiotics, antifungals, or pesticides. Having been the drivers of the golden age of antibiotics in the 1950s and 1960s, technological advancements over the last two decades have revealed that very little of their biosynthetic potential has been exploited so far. Given the great need for new antibiotics due to the emerging antimicrobial resistance crisis, as well as the urgent need for sustainable biobased production of complex molecules, there is a great renewed interest in exploring and engineering the biosynthetic potential of streptomycetes. Here, we describe the Design-Build-Test-Learn (DBTL) cycle for metabolic engineering experiments in streptomycetes and how it can be used for the discovery and production of novel specialized metabolites.

Turning the Screw: Engineering Extreme pH Resistance in Escherichia coli through Combinatorial Synthetic Operons.

Adoption of microorganisms as platforms for sustainable biobased production requires host cells to be able to withstand harsh conditions, usually very distant from those in which these organisms are naturally adapted to thrive. However, novel survival mechanisms unearthed by the study of microbiomes from extreme habitats may be exploited to enhance microbial robustness under the strict conditions needed for different industrial appplications. In this work, synthetic biology approaches were used to engineer enhanced acidic resistance in Escherichia coli through the characterization of a collection of unique operons composed of combinatorial assemblies of three novel genes from an extreme environment and three synthetic ribosome binding sites. The results here presented illustrate the efficacy of combining different metagenomic genes for resistance in synthetic operons, as expression of these gene clusters increased hundred-fold the survival percentage of cells exposed to an acidic shock in minimal media at pH 1.9 under aerobic conditions.

The GHG emissions and economic performance of the Colombian palm oil sector; current status and long-term perspectives

Increasing oil palm plantations, both for obtaining crude palm oil (CPO) and for the production of biobased products, have generated growing concern about the impact of greenhouse gas (GHG) emissions on the environment. Colombia has the potential to produce sustainable biobased products from oil palm. Nevertheless, national GHG emissions have not yet been reported by this sector. Achieving the collection of the total primary data from the oil palm sector, in Colombia, entails a tremendous challenge. Notwithstanding, for this study, the data collection of 70% of the production of fresh fruit bunches (FFB) was achieved. Therefore, current situation of CPO production in Colombia is analyzed, including 1) GHG emissions calculation, 2) net energy ratio (NER), and 3) economic performance. Moreover, the analysis includes two future scenarios, where the CPO production chain is optimized to reduce GHG emissions. Future scenario A produces biodiesel (BD), biogas, cogeneration, and compost; while future scenario B produces BD, biogas, cogeneration, and pellets. The methodology, for all the scenarios, includes life-cycle assessment and economic analysis evaluation. The results show a significant potential for improving the current palm oil production, including a 55% reduction in GHG emissions. The impact of land-use change must be mitigated to reduce GHG emissions. Therefore, a sustainable oil palm expansion should be in areas with low carbon stock or areas suitable/available to the crop (e.g., cropland, pastureland). Avoiding the deforestation of natural forests is required. Besides, crop yield should be increased to minimize the land use, using biomass to produce biobased products, and capture biogas to reduce methane emissions. In the biodiesel production life-cycle, the NER analysis shows the fossil energy consumed is lower than the renewable energy produced. Regarding the economic performance, it shows that in an optimized production chain, the capital expenditure and operational expenditure will decrease by approximately 20%.

The Nanofication and Functionalization of Bacterial Cellulose and Its Applications.

Since economic and environmental issues have become critical in the last several years, the amount of sustainable bio-based production has increased. In this article, microbial polysaccharides, including bacterial cellulose (BC), are analyzed as promising resources with the potential for applications in biofields and non-biofields. Many scientists have established various methods of BC production, nanofication, and functionalization. In particular, this review will address the essential advances in recent years focusing on nanofication methods and nanoficated BC applications as well as functionalization methods and functionalized BC applications.

Comparison of enzymatic saccharification and lignin structure of masson pine and poplar pretreated by p-Toluenesulfonic acid

p-Toluenesulfonic acid (p-TsOH) with the hydrotropic and recyclable properties is widely used for rapid remove of lignin from lignocelluloses at low temperature (<100 °C). In this work, both softwood masson pine and hardwood poplar were pretreated with p-TsOH under different conditions and then subjected to enzymatic hydrolysis to compare the effect of p-TsOH pretreatment on their saccharification and lignin structure. Results showed p-TsOH has sensitive selectivity to lignin structure during pretreatment. Around 95% of lignin in poplar can be dissolved at 80 °C within 30 min, while for masson pine, the delignification is only 50%. Following enzymatic hydrolysis with cellulase loading of 20 FPU/g-cellulose for 72 h, the highest sugar yield of pretreated poplar and masson pine is 92.13% and 29.46%, respectively, which indicates that p-TsOH pretreatment alone works well with hardwoods (poplar). Structural analysis of removed lignin implies that p-TsOH mainly results in the cleavage of β-aryl ether bonds of lignin side chains, and the aromatic structure of lignin keeps intact. p-TsOH pretreatment shows the key advantages of low cost and rapid delignification for highly enzymatic saccharification, and provides a promising and green pathway for the development of low cost and sustainable bio-based products for developing a bio-based economy.

3rd International Conference on Biomass: Accelerating the Technical Development and Commercialization for Sustainable Bio-based Products and Energy

The 3rd International Conference on Biomass 2018 was successfully conducted by Surfactant and Bioenergy Research Center (SBRC), Bogor Agricultural University (IPB) in cooperation with Indonesian Bioenergy Expert Association (IKABI), Indonesian Biogas Association (AbgI), Niigata University of International and Information Studies; University of Science Malaysia (USM), Malaysia; Japan International Research Center for Agricultural Sciences (JIRCAS), Japan; College of Engineering, Villanova University, USA; Biomass Project Research Center, Hiroshima University, Japan; Korea Institute of Energy Research (KIER), Republic of Korea; Graduate School of Energy Science, Kyoto University, Japan; Head of Energy and Environment Unit, Malaysian Palm Oil Board, Malaysia; and was supported by Indonesia Estate Crop Fund Palm Oil; PT Indocement Tunggal Prakarsa Tbk; The Ministry of Research, Technology, and Higher Education Republic of Indonesia; Bogor Agricultural University on 1-2 August 2018 in Bogor, Indonesia. This conference with the theme of Accelerating the Technical Development and Commercialization for Sustainable Bio-based Product and Energy was the third international scientific conference on biomass in Indonesia. This biomass-themed conference is conducted annually to raise current global issues in biomass.The committee accepted 56 of over 95 papers which were presented in the conference and the selected papers are published in this ICB 2018 proceeding. These papers were classified into the following groups:1. Production Technology of Bioenergy2. Biomaterial and Biochemical3. Feedstock, Environment, Sustainability, Policy4. Management, Business, Economy, ICT, Other Products/Applications.

Setting the design space of biorefineries through sustainability values, a practical approach

AbstractSustainable development has become an outstanding aspiration in our society. However, the meaning of sustainability and how it should be operationalized is a complex issue that depends on subjective beliefs and values. To advance toward sustainable biobased production, we present an approach to delimit the design space of biorefineries by considering stakeholders’ values. Concepts from Design for Values were taken as the starting point for this approach, which was further developed with a biojet fuel production case in the Brazilian states of Minas Gerais and São Paulo. Design propositions that considered the interaction between stakeholders’ values, sustainability, and the production system were derived and used to suggest design space boundaries. These design boundaries are indicative, allowing for deliberation during future design activities. Through them, designers are prompted to actively reflect on the interaction between biorefinery systems and the socioeconomic and environmental context around them. By opening the design process to stakeholders’ values, we have developed a constructivist approach to incorporate sustainability in an inclusive and context‐specific manner during the early stages of biorefinery design. © 2017 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

Fatty acid and glucosinolate patterns of seed from Isatis indigotica Fortune as bioproducts for green chemistry

Isatis indigotica Fortune is an herbaceous plant belonging to the Brassicaceae family, whose leaves and roots are rich in active compounds popularly used as natural dyes and/or for their pharmacological activity. Few studies are available on its seeds production and chemical composition. This study evaluated the seed yield and active compounds of I. indigotica Fortune (Chinese woad) with the aim to investigate its intra-species chemotypic, phenotypic and productive variations. A field experiment was carried out in Central Italy under Mediterranean climate, comparing four I. indigotica accessions. The plant phenological, morphological and productive characteristics (siliculas and seed yields) have been evaluated and the seeds analysed for fatty acid composition and glucosinolate patterns. The four accessions, grown as winter annual crop, showed similar phenological development but a different percentage of plants that turn to flower. All the genotypes showed good adaptability to the environmental conditions and good agronomical performances, with good siliculas yield (1.36±0.08tha−1) and oil content (36.8±0.82% w/w). Significant differences among the accessions were observed for the fatty acid and glucosinolate profiles. The oil was rich in mono- and polyunsaturated fatty acid (58% and 32% as mean value, respectively) with major differences for the oleic and α-linolenic acids. The erucic acid content ranged from 16 to 21%. In relation to the glucosinolates, the major differences were recorded for progoitrin, epi-progoitrin, gluconapin and glucobrassicin. The high polyunsaturated fatty acid concentration of I. indigotica seeds, together with its interesting glucosinolate content, open new perspectives for sustainable biobased production.

How kenaf (Hibiscus cannabinus L.) can achieve high yields in Europe and China

Kenaf is an annual spring fibre crop and it is considered as a valuable multipurpose crop due to numerous end uses. Currently, in the framework of an EU project entitled FIBRA (www.fibrafp7.net), kenaf is being investigated in Europe and China as source for sustainable bio-based products. Like all the other cultivated crops, the determination of the appropriate crop management (varieties, sowing dates, plant populations, irrigation, fertilization, weed control and harvesting time) is a key factor for the successful insertion of the crop in the existing agricultural cropping systems with economic benefits. Recently, new kenaf varieties have been released in both USA and China with increased biomass productivity and for some of them with an increased resistance to nematodes and anthracnose. Kenaf sowing should take place in spring as soon as the soil temperature is higher than 15°C. When the crop it is cultivated for its fibre stem the plant population should vary from 200,000 to 500,000plants/ha and the row spacing from 35 to 50cm. In areas that the precipitation is limited, during the hot summer months, irrigation is needed in order the crop to reach high biomass yields. It is a crop with sensitivity to nematodes, especially when it is cultivated in areas with sandy soil and this sensitivity should be taken under consideration in the rotation systems that will be applied. Harvesting time and methods should be adjusted according to the use of the crop (fibre, seeds, fibre and seeds, forage). The development of varieties or hybrids with higher yields (either for stem production or dual purpose varieties for stems and seeds production) and improved resistance to drought as well as to nematodes and anthracnose is considered one of the main challenges for the future of the crop.