Showing papers on "Bioprocess published in 2021"

Challenges in cellulase bioprocess for biofuel applications

Abstract: Increasing population and industrialization caused increased demand for liquid fossil fuels which in turn increases the greenhouse gas emission. Bioethanol produced from lignocellulosic biomass via enzymatic route is a potential alternative to fossil fuels and is environmentally sustainable. Cellulases have been regarded as the limiting factor for bioethanol production from lignocellulosic biomass via enzymes. In the last few decades advances in bioprocesses led to reduction in the cost of cellulases by several folds, enabling bioethanol production to become cost-effective. This is the reason for existence of commercial plants for bioethanol production, however; still there are scope for further improvement in bioprocess for cellulase production and research is ongoing worldwide. Researchers face huge challenge while moving from flask and bioreactor research outcomes from a laboratory scale to the pilot scale production, which has been rarely discussed. This review will present those challenges and its probable solutions. Though commercial cellulases are available, it is highly required to have in-house cellulase production technology to be self-reliant. On-site and integrated cellulase production configuration is popular as it seems to be cost-effective. This review will address advances in bioprocesses and challenges for cellulase production which have surfaced in the last decade.

A Review on Haematococcus pluvialis Bioprocess Optimization of Green and Red Stage Culture Conditions for the Production of Natural Astaxanthin.

Abstract: As the most recognizable natural secondary carotenoid astaxanthin producer, the green microalga Haematococcus pluvialis cultivation is performed via a two-stage process. The first is dedicated to biomass accumulation under growth-favoring conditions (green stage), and the second stage is for astaxanthin evolution under various stress conditions (red stage). This mini-review discusses the further improvement made on astaxanthin production by providing an overview of recent works on H. pluvialis, including the valuable ideas for bioprocess optimization on cell growth, and the current stress-exerting strategies for astaxanthin pigment production. The effects of nutrient constituents, especially nitrogen and carbon sources, and illumination intensity are emphasized during the green stage. On the other hand, the significance of the nitrogen depletion strategy and other exogenous factors comprising salinity, illumination, and temperature are considered for the astaxanthin inducement during the red stage. In short, any factor that interferes with the cellular processes that limit the growth or photosynthesis in the green stage could trigger the encystment process and astaxanthin formation during the red stage. This review provides an insight regarding the parameters involved in bioprocess optimization for high-value astaxanthin biosynthesis from H. pluvialis.

Lentiviral Vector Bioprocessing.

Abstract: Lentiviral vectors (LVs) are potent tools for the delivery of genes of interest into mammalian cells and are now commonly utilised within the growing field of cell and gene therapy for the treatment of monogenic diseases and adoptive therapies such as chimeric antigen T-cell (CAR-T) therapy. This is a comprehensive review of the individual bioprocess operations employed in LV production. We highlight the role of envelope proteins in vector design as well as their impact on the bioprocessing of lentiviral vectors. An overview of the current state of these operations provides opportunities for bioprocess discovery and improvement with emphasis on the considerations for optimal and scalable processing of LV during development and clinical production. Upstream culture for LV generation is described with comparisons on the different transfection methods and various bioreactors for suspension and adherent producer cell cultivation. The purification of LV is examined, evaluating different sequences of downstream process operations for both small- and large-scale production requirements. For scalable operations, a key focus is the development in chromatographic purification in addition to an in-depth examination of the application of tangential flow filtration. A summary of vector quantification and characterisation assays is also presented. Finally, the assessment of the whole bioprocess for LV production is discussed to benefit from the broader understanding of potential interactions of the different process options. This review is aimed to assist in the achievement of high quality, high concentration lentiviral vectors from robust and scalable processes.

One-Pot Chemo-bioprocess of PET Depolymerization and Recycling Enabled by a Biocompatible Catalyst, Betaine

Abstract: Poly(ethylene terephthalate) (PET) has been widely used in various industries due to its unique physical properties. However, PET causes major environmental problems globally due to its low degrada...

Microalgal Co-cultivation for Biofuel Production and Bioremediation: Current Status and Benefits

Abstract: Microalgae have been reported to exhibit mutualistic interactions with other microorganisms like bacteria, filamentous fungi, and yeast and help each other co-exist. The potential of microalgae to perform photosynthesis and accumulate lipids make them suitable candidates for lipid production. Biofuel production from various single oleaginous microorganisms is already in practice. However, the high cost of biomass harvesting, extraction of lipids, and contamination issues are significant challenges of biofuel bioprocess commercialization. Recent microalgal co-culture studies showed considerable potential for easy biomass harvesting and reduction in overall energy consumption cost. Therefore, microalgal co-culture could be an alternative to overcome these constraints and enhance biomass and lipid production. Additionally, the integration of the nutrient sequestration process from potential agro-industrial wastewater using microalgal co-culture can reduce the cost of the substrate requirement for cultivation as well as ecological load. The co-culture in wastewater has shown excellent total phosphate removal efficiencies by microalgae Chlorella sorokiniana and yeast Rhodotorula glutinis, nitrogen removal by microalgae C. sorokiniana with activated sludge, and ammonium-nitrogen removal by C. vulgaris and fungi Aspergillus sp. co-culture. This review summarized the current advances towards biofuel and its value-added production from various microalgae co-culture and compared it with monoculture fermentation. It also includes some critical challenges of co-culturing for the economically viable bioprocess development for biofuel production. Furthermore, techno-economic analysis and life-cycle assessment of co-culture technology were also discussed for biofuel production feasibility from microalgal co-culture.

Microbial and Genetic Resources for Cobalamin (Vitamin B12) Biosynthesis: From Ecosystems to Industrial Biotechnology.

Abstract: Many microbial producers of coenzyme B12 family cofactors together with their metabolically interdependent pathways are comprehensively studied and successfully used both in natural ecosystems dominated by auxotrophs, including bacteria and mammals, and in the safe industrial production of vitamin B12. Metabolic reconstruction for genomic and metagenomic data and functional genomics continue to mine the microbial and genetic resources for biosynthesis of the vital vitamin B12. Availability of metabolic engineering techniques and usage of affordable and renewable sources allowed improving bioprocess of vitamins, providing a positive impact on both economics and environment. The commercial production of vitamin B12 is mainly achieved through the use of the two major industrial strains, Propionobacterium shermanii and Pseudomonas denitrificans, that involves about 30 enzymatic steps in the biosynthesis of cobalamin and completely replaces chemical synthesis. However, there are still unresolved issues in cobalamin biosynthesis that need to be elucidated for future bioprocess improvements. In the present work, we review the current state of development and challenges for cobalamin (vitamin B12) biosynthesis, describing the major and novel prospective strains, and the studies of environmental factors and genetic tools effecting on the fermentation process are reported.

Integrated biomolecular and bioprocess engineering strategies for enhancing the lipid yield from microalgae

Abstract: Algal biofuels have received wide attention in recent years for its potential to reduce the dependence on conventional fossil fuels. Despite the portrayed advantages of high growth rate, carbon sequestration and waste remediation; large scale application of microalgal biofuels is still lacking because of the lower percentage of extractable lipids obtained from the harvested biomass. Thus, there is a substantial impetus to analyse the strategies for enhancing the lipid profile and yield to improve the microalgal biofuel quality as well as to reduce the costs incurred at field scale. Several biochemical and molecular strategies to increase the algal lipid accumulation has gained huge scientific interest in recent years and have opened up new avenues for algal biorefinery. However, the time and cost involved as well as the ecological risks associated with real-time applications often restricts their utilization. The present review gathers a compendium of the key milestones associated with the recent approaches of biochemical, genetic and metabolic engineering for lipid quantity and quality enhancement. Biochemical and engineering aspects of coercing the cells to environmental stress and altering the mode of nutrition has been elucidated. The advancements in genetic and metabolic engineering, the associated risk factors and the future perspectives have been highlighted. Strategic integration of the bioprocess and biomolecular techniques to explore its synergistic impact to rationally engineer microalgae with improved triacylglycerols has been emphasized. Assessment of the long term risks associated herewith can be used to avert the challenges, making algal biofuels a commercial reality in future.

Mixotrophic biorefinery: A promising algal platform for sustainable biofuels and high value coproducts

Abstract: Mixotrophic microalgae cultivation is becoming the most promising and sustainable process for sustainable biosynthesis of biochemicals and biofuels. It offers significantly higher productivity to cope up the key challenges to develop industrial algal processes. Mixotrophic cultivation strategy (MCS) leads to better productivity due to the unique metabolic capacity of microalgae by combining both photosynthesis and oxidative metabolic pathways for biomass generation. The capacity of the mixotrophic phenomenon is being investigated for sustainable bioprocess development ensuring higher energy recovery, economy, environmental and social benefits. However, developments are in pipeline and still to attain a commercial phase. In this article, recent technological developments in MC bioprocess for biofuels production are discussed; synergistic carbon and energy regulation, critical discussion up on commercially important organic carbon sources and their effects on MC bioprocessing have been demonstrated; Moreover, the prospective and challenges of higher-scale MC-linked bioprocessing and future direction on technology development have been addressed.

Bioprocess Control: Current Progress and Future Perspectives.

Abstract: Typical bioprocess comprises of different unit operations wherein a near optimal environment is required for cells to grow, divide, and synthesize the desired product. However, bioprocess control caters to unique challenges that arise due to non-linearity, variability, and complexity of biotech processes. This article presents a review of modern control strategies employed in bioprocessing. Conventional control strategies (open loop, closed loop) along with modern control schemes such as fuzzy logic, model predictive control, adaptive control and neural network-based control are illustrated, and their effectiveness is highlighted. Furthermore, it is elucidated that bioprocess control is more than just automation, and includes aspects such as system architecture, software applications, hardware, and interfaces, all of which are optimized and compiled as per demand. This needs to be accomplished while keeping process requirement, production cost, market value of product, regulatory constraints, and data acquisition requirements in our purview. This article aims to offer an overview of the current best practices in bioprocess control, monitoring, and automation.

Optimising the biosynthesis of oxygenated and acetylated Taxol precursors in Saccharomyces cerevisiae using advanced bioprocessing strategies

Abstract: Taxadien‐5α‐hydroxylase and taxadien‐5α‐ol O‐acetyltransferase catalyse the oxidation of taxadiene to taxadien‐5α‐ol and subsequent acetylation to taxadien‐5α‐yl‐acetate in the biosynthesis of the blockbuster anti‐cancer drug, paclitaxel (Taxol®). Despite decades of research, the promiscuous and multispecific CYP725A4 enzyme remains a major bottleneck in microbial biosynthetic pathway development. In this study, an interdisciplinary approach was applied for the construction and optimisation of the early pathway in Saccharomyces cerevisiae, across a range of bioreactor scales. High‐throughput microscale optimisation enhanced total oxygenated taxane titre to 39.0±5.7 mg/L and total taxane product titres were comparable at micro and mini‐bioreactor scale at 95.4±18.0 and 98.9 mg/L, respectively. The introduction of pH control successfully mitigated a reduction of oxygenated taxane production, enhancing the potential taxadien‐5α‐ol isomer titre to 19.2 mg/L, comparable to the 23.8±3.7 mg/L achieved at microscale. A combination of bioprocess optimisation and increased GC‐MS resolution at 1L bioreactor scale facilitated taxadien‐5α‐yl‐acetate detection with a final titre of 3.7 mg/L. Total oxygenated taxane titres were improved 2.7‐fold at this scale to 78 mg/L, the highest reported titre in yeast. Critical parameters affecting the productivity of the engineered strain were identified across a range of scales, providing a foundation for the development of robust integrated bioprocess control systems. This article is protected by copyright. All rights reserved.

L-asparaginase production review: bioprocess design and biochemical characteristics

Abstract: In the past decades, the production of biopharmaceuticals has gained high interest due to its great sensitivity, specificity, and lower risk of negative effects to patients. Biopharmaceuticals are mostly therapeutic recombinant proteins produced through biotechnological processes. In this context, L-asparaginase (L-asparagine amidohydrolase, L-ASNase (E.C. 3.5.1.1)) is a therapeutic enzyme that has been abundantly studied by researchers due to its antineoplastic properties. As a biopharmaceutical, L-ASNase has been used in the treatment of acute lymphoblastic leukemia (ALL), acute myeloblastic leukemia (AML), and other lymphoid malignancies, in combination with other drugs. Besides its application as a biopharmaceutical, this enzyme is widely used in food processing industries as an acrylamide mitigation agent and as a biosensor for the detection of L-asparagine in physiological fluids at nano-levels. The great demand for L-ASNase is supplied by recombinant enzymes from Escherichia coli and Erwinia chrysanthemi. However, production processes are associated to low yields and proteins associated to immunogenicity problems, which leads to the search for a better enzyme source. Considering the L-ASNase pharmacological and food importance, this review provides an overview of the current biotechnological developments in L-ASNase production and biochemical characterization aiming to improve the knowledge about its production. • Microbial enzyme applications as biopharmaceutical and in food industry • Biosynthesis process: from the microorganism to bioreactor technology • Enzyme activity and kinetic properties: crucial for the final application

Understanding and controlling filamentous growth of fungal cell factories: novel tools and opportunities for targeted morphology engineering.

Abstract: Filamentous fungal cell factories are efficient producers of platform chemicals, proteins, enzymes and natural products. Stirred-tank bioreactors up to a scale of several hundred m³ are commonly used for their cultivation. Fungal hyphae self-assemble into various cellular macromorphologies ranging from dispersed mycelia, loose clumps, to compact pellets. Development of these macromorphologies is so far unpredictable but strongly impacts productivities of fungal bioprocesses. Depending on the strain and the desired product, the morphological forms vary, but no strain- or product-related correlations currently exist to improve process understanding of fungal production systems. However, novel genomic, genetic, metabolic, imaging and modelling tools have recently been established that will provide fundamental new insights into filamentous fungal growth and how it is balanced with product formation. In this primer, these tools will be highlighted and their revolutionary impact on rational morphology engineering and bioprocess control will be discussed.

Bioprocess systems analysis, modeling, estimation, and control

Abstract: The production of monoclonal antibody (mAb) therapeutics, a rapidly growing multi-billion-dollar enterprise in the biopharmaceutical industry, faces major challenges in achieving desired productivity and product quality consistently. These challenges, traditionally addressed by genetic engineering and media recipe development, are now being addressed with process systems engineering (PSE) techniques. In this perspective paper, we discuss how this alternative approach, comprising three components — process modeling, estimation, and control — is being used to address biomanufacturing challenges. We survey the state of current practice for each component, identify existing gaps, and highlight some advances needed to achieve routine implementation of fully automated systems for optimal bioprocess operations.

Bioreactor and bioprocess design issues in enzymatic hydrolysis of lignocellulosic biomass

Abstract: Saccharification of lignocellulosic biomass is a fundamental step in the biorefinery of second generation feedstock. The physicochemical and enzymatic processes for the depolymerization of biomass into simple sugars has been achieved through numerous studies in several disciplines. The present review discusses the development of technologies for enzymatic saccharification in industrial processes. The kinetics of cellulolytic enzymes involved in polysaccharide hydrolysis has been discussed as the starting point for the design of the most promising bioreactor configurations. The main process configurations—proposed so far—for biomass saccharification have been analyzed. Attention was paid to bioreactor configurations, operating modes and possible integrations of this operation within the biorefinery. The focus is on minimizing the effects of product inhibition on enzymes, maximizing yields and concentration of sugars in the hydrolysate, and reducing the impact of enzyme cost on the whole process. The last part of the review is focused on an emerging process based on the catalytic action of laccase applied to lignin depolymerization as an alternative to the consolidated physicochemical pretreatments. The laccases-based oxidative process has been discussed in terms of characteristics that can affect the development of a bioreactor unit where laccases or a laccase-mediator system can be used for biomass delignification.

Pilot-scale demonstration of an end-to-end integrated and continuous biomanufacturing process.

Abstract: There has been increasing momentum recently in the biopharmaceutical industry to transition from traditional batch processes to next-generation integrated and continuous biomanufacturing. This transition from batch to continuous is expected to offer several advantages which, taken together, could significantly improve access to biologics drugs for patients. Despite this recent momentum, there has not been a commercial implementation of a continuous bioprocess reported in the literature. In this study, we describe a successful pilot-scale proof-of-concept demonstration of an end-to-end integrated and continuous bioprocess for the production of a monoclonal antibody (mAb). This process incorporated all of the key unit operations found in a typical mAb production process, including the final steps of virus removal filtration, ultrafiltration, diafiltration, and formulation. The end-to-end integrated process was operated for a total of 25 days and produced a total of 4.9 kg (200 g/day or 2 g/L BRX/day) of the drug substance from a 100-L perfusion bioreactor (BRX) with acceptable product quality and minimal operator intervention. This successful proof-of-concept demonstrates that end-to-end integrated continuous bioprocessing is achievable with current technologies and represents an important step toward the realization of a commercial integrated and continuous bioprocessing process.