Recent advances in rapeseed meal as alternative feedstock for industrial biotechnology
Graphical Abstract
Introduction
Rapeseed (Brassica napus) is a major source of vegetable oil. Significant increase in rapeseed cultivation occurred during the beginning of this century, with an average annual increase of 4.9%. While a lot of rapeseed oil is used in the food industry, this increase was largely driven by the demand of rapeseed oil for biodiesel production, especially in the EU [1], [2]. This led to a peak production of 75 million metric tons of rapeseed in 2017/18 [3]. In recent years, the EU’s demand of rapeseed oil in biodiesel has been reduced by competition from soybean oil methyl ester and palm oil methyl ester [2]. Nevertheless, with current annual consumption of approximately 70–71 million metric tons, rapeseed remains an important oil crop globally [3].
The principal by-product of the industry is rapeseed meal (RSM), which is the post-pressing residue, produced at 39 million metric tons per annum [3]. Currently, RSM is mainly use as animal protein feed [4]. However, direct usage of RSM is limited by other components of the meal. These antinutritional components, including glucosinolates, phenolics, phytates and lignocellulosic fiber, could negatively impact protein solubility and digestibility or lead to formation of toxic compounds [4]. This has limited both the types of animals that can be fed RSM, as well as the proportion of RSM in the total feed. For example, while the complex digestive system of ruminants can tolerate RSM [5], its can only make up to 50% of pig feed and is not recommended for poultry [6]. Such limitations have kept the price of RSM low compared to the more preferable soybean meal, with RSM typically being 100 USD per ton lower in price [3].
Alternatively, RSM could potentially be valorized as a feedstock for industrial biotechnology. RSM contains an extremely high amount of protein (~35% w/w) as well as significant amounts of lignocellulosic material (~12% w/w) [7]. Using RSM-derived media could lead to improved commercial viability of bioproducts, especially those which still rely on purified substrates [8]. The high protein content, coupled with the aforementioned high availability and competitive price versus soybean meal have garnered RSM a significant amount of interest as an alternative source of nitrogen. In many such cases the RSM also acted as a source of micronutrients. The lower portion of lignocellulose typically mean that RSM could not act as a sole source of carbon, especially for the production of bio-products which are secondary metabolite and requires nitrogen-limited conditions.
RSM proteins also have value in itself if isolated for human consumption [4]. Post-protein extraction RSM could have higher proportion of lignocellulose and may have improved potential as a carbon source. RSM also contains other potentially valuable fractions which could be valorized such as phenolics (approximately 5000–7000 μg of sinapic acid equivalents per g) which have potential value due to its antioxidative properties [7], [9] and phytates which could be a valuable source of phosphates for agriculture or biotechnology [10]. Therefore, future potential exists for a whole-crop biorefining scheme based on RSM, involving extraction of valuable compounds followed by fermentation of the residues.
To the best of our knowledge, the last review on the application of RSM in biotechnology was conducted by Lomascolo et al. on both RSM and sunflower meal [7]. At the time, RSM was still largely applied in enzyme production. The pace of progress in RSM valorization had quickened in recent years, with a noticeable increase in the number of publications from 2017 to the present.
In this review the progress made since 2012 is illustrated, as the studies of RSM have expanded to a much greater range of processes, producer organisms and product types, including antimicrobial compounds, biosurfactants, and biopolymers. Fermentation studies which solely focused on improving the feeding values of the RSM are not included. This is because while extremely prevalent within literature, these studies are geared towards the traditional use of RSM as animal feed. In this review various aspects of these recent developments are discussed, including the impact of various pretreatment, hydrolysis and fermentation types, and the role which RSM plays. Areas for future work, such as important knowledge gaps, fields of research with high potential as well as avenues of integrated biorefining are also discussed. Overall, this review highlights the large degree of potential benefit that RSM valorization can offer to a wide array of industrial biotechnological processes in the future.
Section snippets
Recent developments of rapeseed meal usage in industrial biotechnology
In this section, recent advances in the use of RSM for industrial biotechnology are discussed with respect to the different types of products including: enzymes (Table 1), antimicrobials (Table 2), bioactive compounds (Table 3), platform chemicals (Table 4), biosurfactants (Table 5) and biopolymers (Table 6). The role of the RSM in these works are also specified. In many cases RSM was not the only source of nutrients. Some work may simply use RSM as a support matrix for the fermentation, with
Knowledge gaps and future areas of study
Many common knowledge gaps and areas for future study exist across the various products, and should be discussed further. For example, a noticeable gap exists with respect to optimization and scale-up. While many studies (such as those related to enzymes production) have utilized statistical optimization, other products only have proof-of-concepts results. Optimization studies also appears to consider a limited number of variables at a time, therefore more complex multivariate approach could be
Conclusion
In recent years, avenues for RSM valorization via industrial biotechnology have greatly expanded. A wide variety of products have now been produced using RSM, from enzymes to platform chemicals and biopolymers. Techniques utilizing fungal, enzyme, acid, microwave and auto-hydrolysis have been investigated, allowing for improved utilization of RSM-derived compounds by different producer organisms. Additionally, other producer organisms beyond the already known fungal strains have since been
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
References (72)
- et al.
Chapter 18 - Proteins From Canola/Rapeseed: Current Status, Sustainable Protein Sources
(2017) - et al.
Variation of in situ rumen degradation of crude protein and amino acids and in vitro digestibility of undegraded feed protein in rapeseed meals
Animal
(2013) - et al.
Chapter 24 - Bioenergy Technology and Food Industry Waste Valorization for Integrated Production of Polyhydroxyalkanoates, Bioenergy Research: Advances and Applications
(2014) - et al.
Holistic valorization of rapeseed meal utilizing green solvents extraction and biopolymer production with Pseudomonas putida
J. Clean. Prod.
(2019) - et al.
Bioprocess development to add value to canola cake used as substrate for proteolytic enzyme production
Food Bioprod. Process.
(2015) - et al.
Bioconversion of rapeseed meal for the production of a generic microbial feedstock
Enzym. Microb. Technol.
(2010) - et al.
Biorefinery development through utilization of biodiesel industry by-products as sole fermentation feedstock for 1,3-propanediol production
Bioresour. Technol.
(2014) - et al.
Development of a process for the production of nutrient supplements for fermentations based on fungal autolysis
Enzym. Microb. Technol.
(2005) - et al.
Ultrasound-assisted hydrolysis of waste cooking oil catalyzed by homemade lipases
Ultrason. Sonochem.
(2017) - et al.
Production of ε-poly-lysine by Streptomyces albulus PD-1 via solid-state fermentation
Bioresour. Technol.
(2017)
Production of natamycin by Streptomyces gilvosporeus Z28 through solid-state fermentation using agro-industrial residues
Bioresour. Technol.
Rapeseed meal hydrolysate as substrate for microbial astaxanthin production
Biochem. Eng. J.
Current research developments on polyphenolics of rapeseed/canola: a review
Food Chem.
Microbial oil produced from biodiesel by-products could enhance overall production
Bioresour. Technol.
Microbial oil produced from the fermentation of microwave-depolymerised rapeseed meal
Bioresour. Technol. Rep.
Production of poly(3-hydroxybutyrate) from a complete feedstock derived from biodiesel by-products (crude glycerol and rapeseed meal)
Biochem. Eng. J.
Production of free amino acid and short peptide fertilizer from rapeseed meal fermentation using bacillus flexus NJNPD41 for promoting plant growth
Pedosphere
Thermochemical pretreatments for enhancing succinic acid production from industrial hemp (Cannabis sativa L.)
Bioresour. Technol.
A review on the current developments in continuous lactic acid fermentations and case studies utilising inexpensive raw materials
Process Biochem.
Simultaneous saccharification and fermentation of acid-pretreated rapeseed meal for succinic acid production using Actinobacillus succinogenes
Enzym. Microb. Technol.
Hydrothermolysis of rapeseed cake in subcritical water. Effect of reaction temperature and holding time on product composition
Biomass Bioenergy
Occurrence, synthesis and medical application of bacterial polyhydroxyalkanoate
Adv. Drug Deliv. Rev.
The usage of rice straw as a major substrate for the production of surfactin by Bacillus amyloliquefaciens XZ-173 in solid-state fermentation
J. Environ. Manag.
Surfactin analogues produced by Bacillus subtilis strains grown on rapeseed cake
J. Mol. Struct.
A review of sophorolipid production from alternative feedstocks for the development of a localized selection strategy
J. Clean. Prod.
Evaluation of by-products from the biodiesel industry as fermentation feedstock for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) production by Cupriavidus necator
Bioresour. Technol.
Metabolic engineering and pathway construction for biotechnological production of relevant polyhydroxyalkanoates in microorganisms
Biochem. Eng. J.
Recombinant production of poly-(3-hydroxybutyrate) by Bacillus megaterium utilizing millet bran and rapeseed meal hydrolysates
Bioresour. Technol.
Rapeseed meal valorization strategies via nitrogen- and oxygen-limited production of polyhydroxyalkanoates with Pseudomonas putida
Waste Manag.
World markets for vegetable oils and animal fats
Rapeseed and sunflower meal: a review on biotechnology status and challenges
Appl. Microbiol. Biotechnol.
Phytase-based phosphorus recovery process for 20 distinct press cakes
ACS Sustain. Chem. Eng.
Simultaneous hydrolysis with lipase and fermentation of rapeseed cake for iturin A production by Bacillus amyloliquefaciens CX-20
BMC Biotechnol.
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