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Keita VM, Lee YQ, Lakshmanan M, Ow DSW, Staniland P, Staniland J, Savill I, Tee KL, Wong TS, Lee DY. Evaluating oleaginous yeasts for enhanced microbial lipid production using sweetwater as a sustainable feedstock. Microb Cell Fact 2024; 23:63. [PMID: 38402186 PMCID: PMC10893622 DOI: 10.1186/s12934-024-02336-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 02/14/2024] [Indexed: 02/26/2024] Open
Abstract
BACKGROUND Yeasts exhibit promising potential for the microbial conversion of crude glycerol, owing to their versatility in delivering a wide range of value-added products, particularly lipids. Sweetwater, a methanol-free by-product of the fat splitting process, has emerged as a promising alternative feedstock for the microbial utilization of crude glycerol. To further optimize sweetwater utilization, we compared the growth and lipid production capabilities of 21 oleaginous yeast strains under different conditions with various glycerol concentrations, sweetwater types and pH. RESULTS We found that nutrient limitation and the unique carbon composition of sweetwater boosted significant lipid accumulation in several strains, in particular Rhodosporidium toruloides NRRL Y-6987. Subsequently, to decipher the underlying mechanism, the transcriptomic changes of R. toruloides NRRL Y-6987 were further analyzed, indicating potential sugars and oligopeptides in sweetwater supporting growth and lipid accumulation as well as exogenous fatty acid uptake leading to the enhanced lipid accumulation. CONCLUSION Our comparative study successfully demonstrated sweetwater as a cost-effective feedstock while identifying R. toluroides NRRL Y-6987 as a highly promising microbial oil producer. Furthermore, we also suggested potential sweetwater type and strain engineering targets that could potentially enhance microbial lipid production.
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Affiliation(s)
- Valériane Malika Keita
- Department of Chemical & Biological Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, Centros, Singapore, 138668, Singapore
| | - Yi Qing Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea
| | - Meiyappan Lakshmanan
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, Centros, Singapore, 138668, Singapore
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Dave Siak-Wei Ow
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, Centros, Singapore, 138668, Singapore
| | - Paul Staniland
- Croda Europe Ltd., Oak Road, Clough Road, Hull, HU6 7PH, UK
| | | | - Ian Savill
- Croda Europe Ltd., Oak Road, Clough Road, Hull, HU6 7PH, UK
| | - Kang Lan Tee
- Department of Chemical & Biological Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK
| | - Tuck Seng Wong
- Department of Chemical & Biological Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK.
- Evolutor Ltd, The Innovation Centre, 217 Portobello, Sheffield, S1 4DP, UK.
- National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Phahonyothin Road, Khlong Nueang, Khlong Luang, 12120, Pathum Thani, Thailand.
- School of Pharmacy, Bandung Institute of Technology, 10 Coblong, Bandung, West Java, 40132, Indonesia.
| | - Dong-Yup Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea.
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Yang Q, Ran Y, Guo S, Li F, Xiang D, Cao Y, Qiao D, Xu H, Cao Y. Molecular characterization and expression profiling of two flavohemoglobin genes play essential roles in dissolved oxygen and NO stress in Saitozyma podzolica zwy2-3. Int J Biol Macromol 2023; 253:127008. [PMID: 37844810 DOI: 10.1016/j.ijbiomac.2023.127008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 09/13/2023] [Accepted: 09/18/2023] [Indexed: 10/18/2023]
Abstract
Flavohemoglobins (Fhbs) are key enzymes involved in microbial nitrosative stress resistance and nitric oxide degradation. However, the roles of Fhbs in fungi remain largely unknown. In this study, SpFhb1 and SpFhb2, two flavohemoglobin-encoding genes in Saitozyma podzolica zwy2-3 were characterized. Protein structure analysis and molecular docking showed that SpFhbs were conserved in bacteria and fungi. Phylogenetic analysis revealed that SpFhb2 may be acquired through the transfer event of independent horizontal genes from bacteria. The expression levels of SpFhb1 and SpFhb2 showed opposite trend under high/low dissolved oxygen, implying that they may exhibited different functions. Through deletion and overexpression of SpFhbs, we confirmed that SpFhbs were conducive to lipid accumulation under high stress. The sensitivities of ΔFhb mutants to NO stress were significantly increased compared with that in the WT, indicating that they were required for NO detoxification and nitrosative stress resistance in S. podzolica zwy2-3. Furthermore, SpAsg1 was identified that simultaneously regulates SpFhbs, which functions in the lipid accumulation under high/low dissolved oxygen and NO stress in S. podzolica zwy2-3. Overall, two different SpFhbs were identified in this study, providing new insights into the mechanism of lipid accumulation in fungi under high/low dissolved oxygen and NO stress.
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Affiliation(s)
- Qingzhuoma Yang
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Yulu Ran
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Shengtao Guo
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Fazhi Li
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Dongyou Xiang
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Yu Cao
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Dairong Qiao
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Hui Xu
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Yi Cao
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China.
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Transcriptomic Analysis Revealed the Differences in Lipid Accumulation between Spores and Mycelia of Mucor circinelloides WJ11 under Solid–State Fermentation. FERMENTATION 2022. [DOI: 10.3390/fermentation8120667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The oleaginous fungus Mucor circinelloides has been studied for microbial oil production. Solid–state fermentation may be more suitable for lipid production than submerged fermentation due to its special filamentous structure and lower fermentation costs. M. circinelloides WJ11 under solid–state fermentation indicated that the total fatty acid content of mycelia was significantly higher than that of spores (15.0 and 10.4% in mycelia and spores after 192 h, respectively), while the biomass of the fungal mycelia was lower than that of the spores, reaching 78.2 and 86.9 mg/g, respectively. Transcriptomic studies showed that a total of 9069 genes were differentially expressed between spores and mycelia during solid–state fermentation, of which 4748 were up-regulated and 4321 were down-regulated. Among them, triglyceride-related synthases in M. circinelloides were significantly up-regulated in the mycelia. The mRNA expression level of ATP: citrate lyase was obviously increased to provide more acetyl-CoA for fatty acid synthesis in mycelia, moreover, the metabolism of leucine and isoleucine can also produce more acetyl-CoA for lipid accumulation in M. circinelloides. For NADPH supply, the expression of the pentose phosphate pathway was significantly up-regulated in mycelia, while NADP+-dependent malic enzyme was also increased by 9.5-fold under solid–state fermentation. Compared with gene expression in spores, the autophagy pathway was clearly up-regulated in mycelia to prove that autophagy was related to lipid accumulation in M. circinelloides.
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Srenuja D, Shanmugam A, Nair Sinija VR. Novel zero waste tactics for commercial vegetables – recent advances. INTERNATIONAL JOURNAL OF FOOD ENGINEERING 2022. [DOI: 10.1515/ijfe-2022-0126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Commercial vegetables include tomatoes, potatoes, onions, and eggplant due to their surplus production, availability, and affordability. The valorisation of the massive wastage of commercial vegetables and providing a long-term solution has been challenging. The review addresses the implications of biowastes on the environment and fosters the recent investigations into valorising commercial vegetable waste to develop multiple value-added products. It discussed the outcomes of the multiple technologies, majorly on green chemistry extraction, while outlining other methods such as fermentation, enzymatic treatments, 3D printing foods, high-pressure homogenisation, microencapsulation, bio-absorption method, and pyrolysis for their respective vegetable wastes. Agri-residues can be a valuable source for formulating functional ingredients, natural additives, biodiesel, dyes, and animal feed. This comprehensive review proposes a strategy to upcycle low-cost biowaste to boost the economic and ecological benefits. The current review captures the interests and great collaborations between researchers, industrialists, policymakers, waste management bodies, and eco-activists.
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Affiliation(s)
- Dekka Srenuja
- Food Processing Business Incubation Centre, National Institute of Food Technology, Entrepreneurship and Management , Thanjavur , India
| | - Akalya Shanmugam
- Food Processing Business Incubation Centre, National Institute of Food Technology, Entrepreneurship and Management , Thanjavur , India
- Centre of Excellence in Non-Thermal Processing, National Institute of Food Technology, Entrepreneurship and Management , Thanjavur , India
| | - Vadakkepulppara Ramachandran Nair Sinija
- Food Processing Business Incubation Centre, National Institute of Food Technology, Entrepreneurship and Management , Thanjavur , India
- Centre of Excellence in Non-Thermal Processing, National Institute of Food Technology, Entrepreneurship and Management , Thanjavur , India
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Burgstaller L, Löffler S, De Marcellis L, Ghassemi K, Neureiter M. The influence of different carbon sources on growth and single cell oil production in oleaginous yeasts Apiotrichum brassicae and Pichia kudriavzevii. N Biotechnol 2022; 69:1-7. [PMID: 35182781 DOI: 10.1016/j.nbt.2022.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 02/09/2022] [Accepted: 02/12/2022] [Indexed: 12/17/2022]
Abstract
Oleaginous yeasts offer an interesting possibility for renewable lipid production, since the single cell oil accumulated can be based on a wide range of cheap, waste-derived carbon sources. Here, several short chain carboxylic acids and sugars commonly found in these substrates were assessed as carbon sources for Apiotrichum brassicae and Pichia kudriavzevii. While both strains were able to utilize all carbon sources employed, high volumetric lipid productivities (0.4g/Lh) and lipid contents (68%) could be reached particularly with acetic acid as carbon source. Odd-numbered volatile fatty acids led to lower productivities and lipid contents, but the lipids contained unusually high proportions of odd-numbered fatty acids (up to 80% of total fatty acids). These fatty acids are rather uncommon in nature and might offer the possibility for various high value applications. In conclusion both strains are able to utilize a wide range of substrates potentially present in waste-derived substrates. Lipid content and volumetric lipid productivity strongly depend on the carbon source, with even-numbered volatile fatty acids resulting in the highest values. For volatile fatty acids in particular, the carbon source also strongly influences the composition of the lipids produced by the yeast strains.
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Affiliation(s)
- Lukas Burgstaller
- Department for Agrobiotechnology (IFA-Tulln), Institute for Environmental Biotechnology, University of Natural Resources and Life Sciences, Vienna (BOKU), Vienna, Austria
| | - Sebastian Löffler
- Department for Agrobiotechnology (IFA-Tulln), Institute for Environmental Biotechnology, University of Natural Resources and Life Sciences, Vienna (BOKU), Vienna, Austria
| | - Luca De Marcellis
- Department for Agrobiotechnology (IFA-Tulln), Institute for Environmental Biotechnology, University of Natural Resources and Life Sciences, Vienna (BOKU), Vienna, Austria
| | - Khatereh Ghassemi
- Department for Agrobiotechnology (IFA-Tulln), Institute for Environmental Biotechnology, University of Natural Resources and Life Sciences, Vienna (BOKU), Vienna, Austria
| | - Markus Neureiter
- Department for Agrobiotechnology (IFA-Tulln), Institute for Environmental Biotechnology, University of Natural Resources and Life Sciences, Vienna (BOKU), Vienna, Austria.
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Mucoromycota fungi as powerful cell factories for modern biorefinery. Appl Microbiol Biotechnol 2021; 106:101-115. [PMID: 34889982 DOI: 10.1007/s00253-021-11720-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 11/21/2021] [Accepted: 11/24/2021] [Indexed: 12/27/2022]
Abstract
Biorefinery employing fungi can be a strategy for valorizing low-cost rest materials, by-products and wastes into several valuable bioproducts through the fungal fermentation. Mucoromycota fungi are soil fungi with a highly versatile metabolic system that positions them as powerful microbial cell factories for biorefinery applications. Lipids, pigments, chitin/chitosan, polyphosphates, ethanol, organic acids and enzymes are main Mucoromycota products that can be refined from the fermentation process and applied in nutrition, chemical or biofuel industries. In addition, Mucoromycota biomass can be used as it is for specific purposes, such as feed. Mucoromycota fungi can be employed in developing co-production processes, whereby several intra- and extracellular products are simultaneously formed in a single fermentation process, and, thus, economic viability of the process can be improved. This mini review provides a comprehensive overview over the recent advances in the production of valuable metabolites by Mucoromycota fungi and fermentation strategies which could be potentially applied in the industrial biorefinery settings. KEY POINTS: • Biorefineries utilizing Mucoromycota fungi as production cell factories can provide a wide range of bioproducts. • Mucoromycota fungi are able to perform co-production of various metabolites in a single fermentation process. • Versatile metabolism of Mucoromycota allows valorization of a various low-cost substrates such as wastes and rest materials.
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Use of Waste Substrates for the Lipid Production by Yeasts of the Genus Metschnikowia-Screening Study. Microorganisms 2021; 9:microorganisms9112295. [PMID: 34835421 PMCID: PMC8620705 DOI: 10.3390/microorganisms9112295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 10/24/2021] [Accepted: 11/01/2021] [Indexed: 11/30/2022] Open
Abstract
Oleogenic yeasts are characterized by the ability to accumulate increased amounts of lipids under certain conditions. These microbial lipids differ in their fatty acid composition, which allows them to be widely used in the biotechnology industry. The interest of biotechnologists is closely linked to the rising prices of fossil fuels in recent years. Their negative environmental impact is caused by significantly increased demand for biodiesel. The composition of microbial lipids is very similar to vegetable oils, which provides great potential for use in the production of biodiesel. In addition, some oleogenic microorganisms are capable of producing lipids with a high proportion of unsaturated fatty acids. The presented paper’s main aim was to study the production of lipids and lipid substances by yeasts of the genus Metschnikowia, to cultivate crude waste animal fat to study its utilization by yeasts, and to apply the idea of circular economy in the biotechnology of Metschnikowia yeasts. The work focuses on the influence of various stress factors in the cultivation process, such as reduced temperature or nutritional stress through the use of various waste substrates, together with manipulating the ratio of carbon and nitrogen sources in the medium. Yeast production properties were monitored by several instrumental techniques, including gas chromatography and Raman spectroscopy. The amount of lipids and in particular the fatty acid composition varied depending on the strains studied and the culture conditions used. The ability of yeast to produce significant amounts of unsaturated fatty acids was also demonstrated in the work. The most suitable substrate for lipid production was a medium containing glycerol, where the amount of accumulated lipids in the yeast M. pulcherrima 1232 was up to 36%. In our work, the crude animal fat was used for the production of high-value lipids, which to the best of our knowledge is a new result. Moreover, quantitative screening of lipase enzyme activity cultivated on animal fat substrate on selected yeasts of the genus Metschnikowia was performed. We found that for the yeast utilizing glycerol, animal fat seems to be an excellent source of carbon. Therefore, the yeast conversion of crude processed animal fat to value-added products is a valuable process for the biotechnology and food industry.
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8
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Socio-Economic and Environmental Impacts of Biomass Valorisation: A Strategic Drive for Sustainable Bioeconomy. SUSTAINABILITY 2021. [DOI: 10.3390/su13084200] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In the late twentieth century, the only cost-effective opportunity for waste removal cost at least several thousand dollars, but nowadays, a lot of improvement has occurred. The biomass and waste generation problems attracted concerned authorities to identify and provide environmentally friendly sustainable solutions that possess environmental and economic benefits. The present study emphasises the valorisation of biomass and waste produced by domestic and industrial sectors. Therefore, substantial research is ongoing to replace the traditional treatment methods that potentially acquire less detrimental effects. Synthetic biology can be a unique platform that invites all the relevant characters for designing and assembling an efficient program that could be useful to handle the increasing threat for human beings. In the future, these engineered methods will not only revolutionise our lives but practically lead us to get cheaper biofuels, producing bioenergy, pharmaceutics, and various biochemicals. The bioaugmentation approach concomitant with microbial fuel cells (MFC) is an example that is used to produce electricity from municipal waste, which is directly associated with the loading of waste. Beyond the traditional opportunities, herein, we have spotlighted the new advances in pertinent technology closely related to production and reduction approaches. Various integrated modern techniques and aspects related to the industrial sector are also discussed with suitable examples, including green energy and other industrially relevant products. However, many problems persist in present-day technology that requires essential efforts to handle thoroughly because significant valorisation of biomass and waste involves integrated methods for timely detection, classification, and separation. We reviewed and proposed the anticipated dispensation methods to overcome the growing stream of biomass and waste at a distinct and organisational scale.
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Mhlongo SI, Ezeokoli OT, Roopnarain A, Ndaba B, Sekoai PT, Habimana O, Pohl CH. The Potential of Single-Cell Oils Derived From Filamentous Fungi as Alternative Feedstock Sources for Biodiesel Production. Front Microbiol 2021; 12:637381. [PMID: 33584636 PMCID: PMC7876240 DOI: 10.3389/fmicb.2021.637381] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 01/07/2021] [Indexed: 11/13/2022] Open
Abstract
Microbial lipids, also known as single-cell oils (SCOs), are highly attractive feedstocks for biodiesel production due to their fast production rates, minimal labor requirements, independence from seasonal and climatic changes, and ease of scale-up for industrial processing. Among the SCO producers, the less explored filamentous fungi (molds) exhibit desirable features such as a repertoire of hydrolyzing enzymes and a unique pellet morphology that facilitates downstream harvesting. Although several oleaginous filamentous fungi have been identified and explored for SCO production, high production costs and technical difficulties still make the process less attractive compared to conventional lipid sources for biodiesel production. This review aims to highlight the ability of filamentous fungi to hydrolyze various organic wastes for SCO production and explore current strategies to enhance the efficiency and cost-effectiveness of the SCO production and recovery process. The review also highlights the mechanisms and components governing lipogenic pathways, which can inform the rational designs of processing conditions and metabolic engineering efforts for increasing the quality and accumulation of lipids in filamentous fungi. Furthermore, we describe other process integration strategies such as the co-production with hydrogen using advanced fermentation processes as a step toward a biorefinery process. These innovative approaches allow for integrating upstream and downstream processing units, thus resulting in an efficient and cost-effective method of simultaneous SCO production and utilization for biodiesel production.
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Affiliation(s)
- Sizwe I. Mhlongo
- Discipline of Medical Microbiology, School of Laboratory Medicine and Medical Sciences, Medical School, University of KwaZulu-Natal, Durban, South Africa
| | - Obinna T. Ezeokoli
- Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, South Africa
| | - Ashira Roopnarain
- Microbiology and Environmental Biotechnology Research Group, Institute for Soil, Climate and Water, Agricultural Research Council, Pretoria, South Africa
| | - Busiswa Ndaba
- Microbiology and Environmental Biotechnology Research Group, Institute for Soil, Climate and Water, Agricultural Research Council, Pretoria, South Africa
| | - Patrick T. Sekoai
- The School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Olivier Habimana
- The School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Carolina H. Pohl
- Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, South Africa
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Zhang L, Loh KC, Kuroki A, Dai Y, Tong YW. Microbial biodiesel production from industrial organic wastes by oleaginous microorganisms: Current status and prospects. JOURNAL OF HAZARDOUS MATERIALS 2021; 402:123543. [PMID: 32739727 DOI: 10.1016/j.jhazmat.2020.123543] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/16/2020] [Accepted: 07/20/2020] [Indexed: 06/11/2023]
Abstract
This review aims to encourage the technical development of microbial biodiesel production from industrial-organic-wastes-derived volatile fatty acids (VFAs). To this end, this article summarizes the current status of several key technical steps during microbial biodiesel production, including (1) acidogenic fermentation of bio-wastes for VFA collection, (2) lipid accumulation in oleaginous microorganisms, (3) microbial lipid extraction, (4) transesterification of microbial lipids into crude biodiesel, and (5) crude biodiesel purification. The emerging membrane-based bioprocesses such as electrodialysis, forward osmosis and membrane distillation, are promising approaches as they could help tackle technical challenges related to the separation and recovery of VFAs from the fermentation broth. The genetic engineering and metabolic engineering approaches could be applied to design microbial species with higher lipid productivity and rapid growth rate for enhanced fatty acids synthesis. The enhanced in situ transesterification technologies aided by microwave, ultrasound and supercritical solvents are also recommended for future research. Technical limitations and cost-effectiveness of microbial biodiesel production from bio-wastes are also discussed, in regard to its potential industrial development. Based on the overview on microbial biodiesel technologies, an integrated biodiesel production line incorporating all the critical technical steps is proposed for unified management and continuous optimization for highly efficient biodiesel production.
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Affiliation(s)
- Le Zhang
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore
| | - Kai-Chee Loh
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore
| | - Agnès Kuroki
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore
| | - Yanjun Dai
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yen Wah Tong
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore.
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11
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Chawla K, Kaur S, Kaur R, Bhunia RK. Metabolic engineering of oleaginous yeasts to enhance single cell oil production. J FOOD PROCESS ENG 2020. [DOI: 10.1111/jfpe.13634] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kirti Chawla
- Plant Tissue Culture and Genetic Engineering National Agri‐Food Biotechnology Institute (NABI) Mohali Punjab India
| | - Sumandeep Kaur
- Department of Biotechnology, Sector‐25 Panjab University Chandigarh India
| | - Ranjeet Kaur
- Department of Genetics University of Delhi South Campus New Delhi India
| | - Rupam Kumar Bhunia
- Plant Tissue Culture and Genetic Engineering National Agri‐Food Biotechnology Institute (NABI) Mohali Punjab India
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12
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Aburatani S, Ishiya K, Itoh T, Hayashi T, Taniguchi T, Takaku H. Inference of Regulatory System for TAG Biosynthesis in Lipomyces starkeyi. Bioengineering (Basel) 2020; 7:bioengineering7040148. [PMID: 33227954 PMCID: PMC7711605 DOI: 10.3390/bioengineering7040148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/14/2020] [Accepted: 11/18/2020] [Indexed: 12/23/2022] Open
Abstract
Improving the bioproduction ability of efficient host microorganisms is a central aim in bioengineering. To control biosynthesis in living cells, the regulatory system of the whole biosynthetic pathway should be clearly understood. In this study, we applied our network modeling method to infer the regulatory system for triacylglyceride (TAG) biosynthesis in Lipomyces starkeyi, using factor analyses and structural equation modeling to construct a regulatory network model. By factor analysis, we classified 89 TAG biosynthesis-related genes into nine groups, which were considered different regulatory sub-systems. We constructed two different types of regulatory models. One is the regulatory model for oil productivity, and the other is the whole regulatory model for TAG biosynthesis. From the inferred oil productivity regulatory model, the well characterized genes DGA1 and ACL1 were detected as regulatory factors. Furthermore, we also found unknown feedback controls in oil productivity regulation. These regulation models suggest that the regulatory factor induction targets should be selected carefully. Within the whole regulatory model of TAG biosynthesis, some genes were detected as not related to TAG biosynthesis regulation. Using network modeling, we reveal that the regulatory system is helpful for the new era of bioengineering.
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Affiliation(s)
- Sachiyo Aburatani
- Computational Bio Big-Data Open Innovation Laboratory (CBBD-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Tokyo 305-8568, Japan
- Correspondence: (S.A.); (H.T.); Tel.: +81-3-3599-8712 (S.A.); +81-250-25-5119 (H.T.)
| | - Koji Ishiya
- BPRI, National Institute of Advance Industrial Science and Technology (AIST), Sapporo 062-8517, Japan;
| | - Toshikazu Itoh
- Mitsubishi Research Institute, Inc., Chiyoda District, Tokyo 100-8141, Japan; (T.I.); (T.H.); (T.T.)
| | - Toshihiro Hayashi
- Mitsubishi Research Institute, Inc., Chiyoda District, Tokyo 100-8141, Japan; (T.I.); (T.H.); (T.T.)
| | - Takeaki Taniguchi
- Mitsubishi Research Institute, Inc., Chiyoda District, Tokyo 100-8141, Japan; (T.I.); (T.H.); (T.T.)
| | - Hiroaki Takaku
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
- Correspondence: (S.A.); (H.T.); Tel.: +81-3-3599-8712 (S.A.); +81-250-25-5119 (H.T.)
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Radha P, Prabhu K, Jayakumar A, AbilashKarthik S, Ramani K. Biochemical and kinetic evaluation of lipase and biosurfactant assisted ex novo synthesis of microbial oil for biodiesel production by Yarrowia lipolytica utilizing chicken tallow. Process Biochem 2020. [DOI: 10.1016/j.procbio.2020.05.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Lipid metabolism of the oleaginous yeast Lipomyces starkeyi. Appl Microbiol Biotechnol 2020; 104:6141-6148. [DOI: 10.1007/s00253-020-10695-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/13/2020] [Accepted: 05/18/2020] [Indexed: 02/07/2023]
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15
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Panwar D, Panesar PS, Chopra HK. Recent Trends on the Valorization Strategies for the Management of Citrus By-products. FOOD REVIEWS INTERNATIONAL 2019. [DOI: 10.1080/87559129.2019.1695834] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Divyani Panwar
- Food Biotechnology Research Laboratory, Department of Food Engineering and Technology, Sant Longowal Institute of Engineering and Technology, Longowal, India
| | - Parmjit S. Panesar
- Food Biotechnology Research Laboratory, Department of Food Engineering and Technology, Sant Longowal Institute of Engineering and Technology, Longowal, India
| | - Harish K. Chopra
- Department of Chemistry, Sant Longowal Institute of Engineering and Technology, Longowal, India
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Qian X, Gorte O, Chen L, Zhang W, Dong W, Ma J, Jiang M, Xin F, Ochsenreither K. Co-production of single cell oil and gluconic acid using oleaginous Cryptococcus podzolicus DSM 27192. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:127. [PMID: 31139257 PMCID: PMC6528270 DOI: 10.1186/s13068-019-1469-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 05/15/2019] [Indexed: 06/01/2023]
Abstract
BACKGROUND The co-production of single cell oil (SCO) with value-added products could improve the economic viability of industrial SCO production. The newly isolated oleaginous yeast Cryptococcus podzolicus DSM 27192 was able to co-produce SCO intracellularly and gluconic acid (GA) extracellularly. In this study, the metabolic regulation of carbon distribution between SCO and GA through process optimization was comprehensively investigated. RESULTS The carbon flow distribution between SCO and GA was significantly influenced by the cultivation conditions, such as nitrogen sources, glucose concentration and dissolved oxygen concentration. It was found that organic nitrogen sources were beneficial for SCO accumulation, while GA production was decreased. Dissolved oxygen concentration (DOC) was found to enhance SCO accumulation, while high glucose concentration was more favorable for GA accumulation. Hence, a two-stage DOC or glucose concentration-controlled strategy was designed to improve cell growth and direct carbon distribution between SCO and GA. Moreover, C. podzolicus DSM 27192 could degrade its stored lipids to synthesize GA in the late stationary phase, although considerable amounts of glucose remained unconsumed in the culture medium, indicating the importance of fermentation time control in co-production systems. All these observations provide opportunity to favor either the production of SCO or GA or rather their simultaneous production. CONCLUSIONS Co-production of SCO and GA by C. podzolicus DSM 27192 can improve the economical value for microbial lipid-derived biodiesel production. Moreover, the results of the proposed co-production strategy might give guidance for other co-production systems.
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Affiliation(s)
- Xiujuan Qian
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
| | - Olga Gorte
- Institute of Process Engineering in Life Sciences, Section II: Technical Biology, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany
| | - Lin Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
| | - Wenming Zhang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816 People’s Republic of China
| | - Weiliang Dong
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816 People’s Republic of China
| | - Jiangfeng Ma
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816 People’s Republic of China
| | - Min Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816 People’s Republic of China
| | - Fengxue Xin
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211816 People’s Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816 People’s Republic of China
| | - Katrin Ochsenreither
- Institute of Process Engineering in Life Sciences, Section II: Technical Biology, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany
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17
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Liu L, Song J, Li Y, Li P, Wang H. Robust and cost-saving static solid cultivation method for lipid production using the chlamydospores of Phanerochaete chrysosporium. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:123. [PMID: 31139253 PMCID: PMC6528298 DOI: 10.1186/s13068-019-1464-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 05/10/2019] [Indexed: 05/07/2023]
Abstract
BACKGROUND During current submerged fermentation for microbial lipid production, the large-scale reactor operations inevitably consume substantial amounts of water and electricity for aeration, stirring, and temperature control and result in the operational costs almost exceeding the biodiesel value produced. Thus, developing a novel low-cost cultivation strategy is urgently needed by microbial lipid industry. RESULTS The filamentous fungus Phanerochaete chrysosporium can synthesize and accumulate lipids via static solid cultivation. The conversion efficiency of substrates to lipids reaches 0.277 g/g substrate after optimization of the following cultivation factors: humidity, solid medium thickness, temperature, and rotary speed. The lipids obtained by static solid cultivation differ in component and relative content from those achieved by submerged cultivation. Laser scanning confocal microscopy reveals that numerous chlamydospores filled with lipids appear during static solid cultivation, and the fungal morphological change explains why static solid cultivation is superior in lipid yield compared with submerged fermentation. The genes coding the enzymes related to fatty acid elongation and degradation are differently expressed during static solid cultivation, which presents an answer to the appearance of abundant saturated long-chain fatty acids (93.6% in total fatty acids) in chlamydospores. In addition, engineering viability and cost-benefit analysis show that the conversion of wheat bran and glucose to lipid by the fungus is efficient. More importantly, the solid cultivation incurs only a small reactor operational cost because neither cooling water nor electrical equipment, including aerator, stirrer, and the temperature control system, is used. CONCLUSIONS This study developed a robust and cost-saving solid fermentation method without an aerator, stirrer, and temperature control system to produce microbial lipids using the chlamydospores of P. chrysosporium. Compared with conventional submerged fermentation, the solid cultivation strategy is promising because it diminishes most of the reactor operational costs, including water and power expenses.
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Affiliation(s)
- Lei Liu
- College of Life Sciences, Henan Normal University, Xinxiang, 453007 China
| | - Jie Song
- College of Life Sciences, Henan Normal University, Xinxiang, 453007 China
- Advanced Environmental Biotechnology Center, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore, 637141 Singapore
| | - Yi Li
- College of Life Sciences, Henan Normal University, Xinxiang, 453007 China
| | - Ping Li
- College of Life Sciences, Henan Normal University, Xinxiang, 453007 China
| | - Hailei Wang
- College of Life Sciences, Henan Normal University, Xinxiang, 453007 China
- Advanced Environmental Biotechnology Center, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore, 637141 Singapore
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Athenaki M, Gardeli C, Diamantopoulou P, Tchakouteu S, Sarris D, Philippoussis A, Papanikolaou S. Lipids from yeasts and fungi: physiology, production and analytical considerations. J Appl Microbiol 2018; 124:336-367. [DOI: 10.1111/jam.13633] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 09/20/2017] [Accepted: 10/27/2017] [Indexed: 12/24/2022]
Affiliation(s)
- M. Athenaki
- Department of Food Science and Human Nutrition; Agricultural University of Athens; Athens Greece
| | - C. Gardeli
- Department of Food Science and Human Nutrition; Agricultural University of Athens; Athens Greece
| | - P. Diamantopoulou
- Laboratory of Edible Fungi; Institute of Technology of Agricultural Products; Hellenic Agricultural Organization ‘Demeter’; Lycovryssi Greece
| | - S.S. Tchakouteu
- Department of Food Science and Human Nutrition; Agricultural University of Athens; Athens Greece
| | - D. Sarris
- Department of Food Science and Human Nutrition; Agricultural University of Athens; Athens Greece
| | - A. Philippoussis
- Laboratory of Edible Fungi; Institute of Technology of Agricultural Products; Hellenic Agricultural Organization ‘Demeter’; Lycovryssi Greece
| | - S. Papanikolaou
- Department of Food Science and Human Nutrition; Agricultural University of Athens; Athens Greece
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Gardeli C, Athenaki M, Xenopoulos E, Mallouchos A, Koutinas AA, Aggelis G, Papanikolaou S. Lipid production and characterization by Mortierella (Umbelopsis) isabellina cultivated on lignocellulosic sugars. J Appl Microbiol 2017; 123:1461-1477. [PMID: 28921786 DOI: 10.1111/jam.13587] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 08/24/2017] [Accepted: 08/30/2017] [Indexed: 01/01/2023]
Abstract
AIMS To study and characterize the lipids produced by Mortierella (Umbelopsis) isabellina, during its growth on mixtures of glucose and xylose. METHODS AND RESULTS Glucose and xylose were utilized as carbon sources, solely or in blends, under nitrogen-limited conditions, in batch-flask trials (initial sugars at 80 g l-1 ). Significant lipid production (maximum lipid 17·8 g l-1 ; lipid in DCW 61·0% w/w; lipid on glucose consumed 0·23 g g-1 ) occurred on glucose employed solely, while xylose concentration in the growth medium was conversely correlated with lipid accumulation. With increasing xylose concentrations into the blend, lipid storage decreased while xylitol in significant concentrations (up to 24 g l-1 ) was produced. Irrespective of the sugar blend employed, significant quantities of endopolysaccharides were detected in the first growth steps (in the presence of nitrogen into the medium or barely after its disappearance) while lipids were stored thereafter. Neutral lipids, mainly composed of triacylglycerols, were the main microbial lipid fraction. Phospholipids were quantified both through fractionation and subsequent gravimetric determination and also through determination of phosphorus, and it seemed that the second method was more accurate. Phospholipids were mainly composed of phosphatidylcholine and another nonidentified compound presumably being phosphatidyldimethylethanolamine. CONCLUSIONS Mortierella isabellina is suitable to convert lignocellulosic sugars into lipids. SIGNIFICANCE AND IMPACT OF THE STUDY Differentiations between metabolism on xylose and glucose were reported. Moreover, this is one of the first reports indicating extensive analysis of microbial lipids produced by M. isabellina.
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Affiliation(s)
- C Gardeli
- Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - M Athenaki
- Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - E Xenopoulos
- Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - A Mallouchos
- Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - A A Koutinas
- Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - G Aggelis
- Department of Biology, University of Patras, Patras, Greece
| | - S Papanikolaou
- Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
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Puyol D, Batstone DJ, Hülsen T, Astals S, Peces M, Krömer JO. Resource Recovery from Wastewater by Biological Technologies: Opportunities, Challenges, and Prospects. Front Microbiol 2017; 7:2106. [PMID: 28111567 PMCID: PMC5216025 DOI: 10.3389/fmicb.2016.02106] [Citation(s) in RCA: 158] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 12/13/2016] [Indexed: 01/07/2023] Open
Abstract
Limits in resource availability are driving a change in current societal production systems, changing the focus from residues treatment, such as wastewater treatment, toward resource recovery. Biotechnological processes offer an economic and versatile way to concentrate and transform resources from waste/wastewater into valuable products, which is a prerequisite for the technological development of a cradle-to-cradle bio-based economy. This review identifies emerging technologies that enable resource recovery across the wastewater treatment cycle. As such, bioenergy in the form of biohydrogen (by photo and dark fermentation processes) and biogas (during anaerobic digestion processes) have been classic targets, whereby, direct transformation of lipidic biomass into biodiesel also gained attention. This concept is similar to previous biofuel concepts, but more sustainable, as third generation biofuels and other resources can be produced from waste biomass. The production of high value biopolymers (e.g., for bioplastics manufacturing) from organic acids, hydrogen, and methane is another option for carbon recovery. The recovery of carbon and nutrients can be achieved by organic fertilizer production, or single cell protein generation (depending on the source) which may be utilized as feed, feed additives, next generation fertilizers, or even as probiotics. Additionlly, chemical oxidation-reduction and bioelectrochemical systems can recover inorganics or synthesize organic products beyond the natural microbial metabolism. Anticipating the next generation of wastewater treatment plants driven by biological recovery technologies, this review is focused on the generation and re-synthesis of energetic resources and key resources to be recycled as raw materials in a cradle-to-cradle economy concept.
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Affiliation(s)
- Daniel Puyol
- Group of Chemical and Environmental Engineering, School of Experimental Sciences and Technology, King Juan Carlos UniversityMostoles, Spain
| | - Damien J. Batstone
- Advanced Water Management Centre, University of Queensland, BrisbaneQLD, Australia
- CRC for Water Sensitive Cities, ClaytonVIC, Australia
| | - Tim Hülsen
- Advanced Water Management Centre, University of Queensland, BrisbaneQLD, Australia
- CRC for Water Sensitive Cities, ClaytonVIC, Australia
| | - Sergi Astals
- Advanced Water Management Centre, University of Queensland, BrisbaneQLD, Australia
| | - Miriam Peces
- Centre for Solid Waste Bioprocessing, School of Civil Engineering, University of Queensland, BrisbaneQLD, Australia
| | - Jens O. Krömer
- Advanced Water Management Centre, University of Queensland, BrisbaneQLD, Australia
- Centre for Microbial Electrochemical Systems, University of Queensland, BrisbaneQLD, Australia
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Zielewicz E. Effects of ultrasonic disintegration of excess sewage sludge. Top Curr Chem (Cham) 2016; 374:67. [PMID: 27620187 DOI: 10.1007/s41061-016-0068-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 08/23/2016] [Indexed: 11/25/2022]
Abstract
Breaking down sludge floc (sonodyspergation effect) and destruction of the cell membranes of microorganisms forming floc is a direct effect of ultrasonic disintegration of sludge excess. This results in release of organic material by liquid sludge (the sonolysis effect). Desired technological effects of the disintegration are: to shorten the hydrolytic phase of fermentation, to increase the production of biogas (source of renewable energy) and an increased mineralization (stability) of fermented sludge. The presented study demonstrates research covering thickened excess sludge of various physicochemical properties, collected from nine municipal sewage treatment plants. The sludge was subjected to ultrasonic disintegration using three differently constructed disintegrators and different proportions of sonification area. Direct effects of disintegration were monitored and recorded using selected indicators describing changes in the properties of sludge and increase of substance dispersed and dissolved in the supernatant liquid to be filtered. Studies have demonstrated that those (direct) effects of ultrasonic disintegration depend on the physicochemical properties of the sludge (foremost the concentration of dry solids) that determine their variable susceptibility to the disintegration methods. The direct effects also depend on optimal process conditions (which consist of the construction of the ultrasonic disintegrator), the geometric proportions of the sonication area and the operating parameters of disintegration (which could be appropriately matched to the characteristics of sludge). The most preferable results were obtained for ultrasonic disintegration of sludge with a dry matter concentration C 0 < 4.2 %. The highest effect of sonolysis-an almost 30-fold increase in the COD dissolved in the supernatant-was obtained for the sludge of lowest dry matter (C 0 = 2.0 %), which was sonicated in a reactor with a short transducer of the largest radiating surface area, as well as the lowest ratio between this area and area of reactor. The best effects of disagglomeration of flocks have corresponded with the high value of power density U UD = 880-900 WL(-1).
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Affiliation(s)
- Ewa Zielewicz
- Institute of Water and Wastewater Engineering, Silesian University of Technology, Konarskiego18A, 44-100, Gliwice, Poland.
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Zhang Z, O’Hara IM, Mundree S, Gao B, Ball AS, Zhu N, Bai Z, Jin B. Biofuels from food processing wastes. Curr Opin Biotechnol 2016; 38:97-105. [DOI: 10.1016/j.copbio.2016.01.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 01/23/2016] [Accepted: 01/26/2016] [Indexed: 11/17/2022]
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