The green revolution of food waste upcycling to produce polyhydroxyalkanoates.

This review emphasizes the urgent need for food waste upcycling as a response to the mounting global food waste crisis. Focusing on polyhydroxyalkanoates (PHAs) as an alternative to traditional plastics, it examines the potential of various food wastes as feedstock for microbial fermentation and PHA production. The upcycling of food waste including cheese whey, waste cooking oil, coffee waste, and animal fat is an innovative practice for food waste management. This approach not only mitigates environmental impacts but also contributes to sustainable development and economic growth. Downstream processing techniques for PHAs are discussed, highlighting their role in obtaining high-quality materials. The study also addresses sustainability considerations, emphasizing biodegradability and recycling, while acknowledging the challenges associated with this path.

Controlled production of a polyhydroxyalkanoate (PHA) tetramer containing different mole fraction of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3 HV), 4 HV and 5 HV units by engineered Cupriavidus necator.

Polyhydroxyalkanoates (PHAs) are promising alternatives to existing petrochemical-based plastics because of their bio-degradable properties. However, the limited structural diversity of PHAs has hindered their application. In this study, high mole-fractions of Poly (39 mol% 3HB-co-17 mol% 3 HV-co-44 mol% 4 HV) and Poly (25 mol% 3HB-co-75 mol% 5 HV) were produced from 4- hydroxyvaleric acid and 5-hydroxyvaleric acid, using Cupriavidus necator PHB-4 harboring the gene phaCBP-M-CPF4 with modified sequences. In addition, the complex toxicity of precursor mixtures was tested, and it was confirmed that the engineered C. necator was capable of synthesizing Poly (32 mol% 3HB-co-11 mol% 3 HV-co-25 mol% 4 HV-co-32 mol% 5 HV) at low mixture concentrations. Correlation analyses of the precursor ratio and the monomeric mole fractions indicated that each mole fractions could be precisely controlled using the precursor proportion. Physical property analysis confirmed that Poly (3HB-co-3 HV-co-4 HV) is a rubber-like amorphous polymer and Poly (3HB-co-5 HV) has a high tensile strength and elongation at break. Poly (3HB-co-3 HV-co-4 HV-co-5 HV) had a much lower glass transition temperature than the co-, terpolymers containing 3 HV, 4 HV and 5 HV. This study expands the range of possible physical properties of PHAs and contributes to the realization of custom PHA production by suggesting a method for producing PHAs with various physical properties through mole-fraction control of 3 HV, 4 HV and 5 HV.

Establishment of efficient 5-hydroxyvaleric acid production system by regenerating alpha-ketoglutaric acid and its application in poly(5-hydroxyvaleric acid) production.

5-hydroxyvaleric acid (5-HV) is a versatile C5 intermediate of bio-based high-value chemical synthesis pathways. However, 5-HV production faces a few shortcomings involving the supply of cofactors, especially α-ketoglutaric acid (α-KG). Herein, we established a two-cell biotransformation system by introducing L-glutamate oxidase (GOX) to regenerate α-KG. Additionally, the catalase KatE was adapted to inhibit α-KG degradation by the H2O2 produced during GOX reaction. We searched for the best combination of genes and vectors and optimized the biotransformation conditions to maximize GOX effectiveness. Under the optimized conditions, 5-HV pathway with GOX showed 1.60-fold higher productivity than that of without GOX, showing 11.3 g/L titer. Further, the two-cell system with GOX and KatE was expanded to produce poly(5-hydroxyvaleric acid) (P(5HV)), and it reached at 412 mg/L of P(5HV) production and 20.5% PHA contents when using the biotransformation supernatant. Thus, the two-cell biotransformation system with GOX can potentially give the practical and economic alternative of 5-HV production using bio-based methods. We also propose direct utilization of 5-HV from bioconversion for P(5HV) production.

Reproducible Polybutylene Succinate (PBS)-Degrading Artificial Consortia by Introducing the Least Type of PBS-Degrading Strains.

Polybutylene succinate (PBS) stands out as a promising biodegradable polymer, drawing attention for its potential as an eco-friendly alternative to traditional plastics due to its biodegradability and reduced environmental impact. In this study, we aimed to enhance PBS degradation by examining artificial consortia composed of bacterial strains. Specifically, Terribacillus sp. JY49, Bacillus sp. JY35, and Bacillus sp. NR4 were assessed for their capabilities and synergistic effects in PBS degradation. When only two types of strains, Bacillus sp. JY35 and Bacillus sp. NR4, were co-cultured as a consortium, a notable increase in degradation activity toward PBS was observed compared to their activities alone. The consortium of Bacillus sp. JY35 and Bacillus sp. NR4 demonstrated a remarkable degradation yield of 76.5% in PBS after 10 days. The degradation of PBS by the consortium was validated and our findings underscore the potential for enhancing PBS degradation and the possibility of fast degradation by forming artificial consortia, leveraging the synergy between strains with limited PBS degradation activity. Furthermore, this study demonstrated that utilizing only two types of strains in the consortium facilitates easy control and provides reproducible results. This approach mitigates the risk of losing activity and reproducibility issues often associated with natural consortia.

Indigo production goes green: a review on opportunities and challenges of fermentative production.

Indigo is a widely used dye in various industries, such as textile, cosmetics, and food. However, traditional methods of indigo extraction and processing are associated with environmental and economic challenges. Fermentative production of indigo using microbial strains has emerged as a promising alternative that offers sustainability and cost-effectiveness. This review article provides a critical overview of microbial diversity, metabolic pathways, fermentation strategies, and genetic engineering approaches for fermentative indigo production. The advantages and limitations of different indigo production systems and a critique of the current understanding of indigo biosynthesis are discussed. Finally, the potential application of indigo in other sectors is also discussed. Overall, fermentative production of indigo offers a sustainable and bio-based alternative to synthetic methods and has the potential to contribute to the development of sustainable and circular biomanufacturing.

Understanding microplastic pollution: Tracing the footprints and eco-friendly solutions.

Microplastics (MPs) pollution has emerged as a critical environmental issue with far-reaching consequences for ecosystems and human health. These are plastic particles measuring <5 mm and are categorized as primary and secondary based on their origin. Primary MPs are used in various products like cosmetics, scrubs, body wash, and toothpaste, while secondary MPs are generated through the degradation of plastic products. These have been detected in seas, rivers, snow, indoor air, and seafood, posing potential risks to human health through the food chain. Detecting and quantifying MPs are essential to understand their distribution and abundance in the environment. Various microscopic (fluorescence microscopy, scanning electron microscopy) and spectroscopy techniques (FTIR, Raman spectroscopy, X-ray photoelectron spectroscopy) have been reported to analyse MPs. Despite the challenges in scalable removal methods, biological systems have emerged as promising options for eco-friendly MPs remediation. Algae, bacteria, and fungi have shown the potential to adsorb and degrade MPs in wastewater treatment plants (WWTPs) offering hope for mitigating this global crisis. This review examines the sources, impacts, detection, and biological removal of MPs, highlighting future directions in this crucial field of environmental conservation. By fostering global collaboration and innovative research a path towards a cleaner and healthier planet for future generations can be promised.

Positive effect of phasin in biohydrogen production of non polyhydroxybutyrate-producing Clostridium acetobutylicum ATCC 824.

In this study, the goal was to enhance the tolerance of Clostridium acetobutylicum ATCC 824 to biomass-based inhibitory compounds for biohydrogen production and evaluate various known genes that enhance the production of biochemicals in various hosts. The introduction of phaP, the major polyhydroxyalkanoate granule-associated protein that has been reported as a chaperone-like protein resulted in increased tolerance to inhibitors and leads to higher levels of hydrogen production, cell growth, and glucose consumption in the presence of these inhibitors. It was observed that the introduction of phaP led to an increase in the transcription of the hydrogenase gene, whereas transcription of the chaperone functional genes decreased compared to the wild type. Finally, the introduction of phaP could significantly enhance biohydrogen production by 2.6-fold from lignocellulosic hydrolysates compared to that of wild type. These findings suggested that the introduction of phaP could enhance growth and biohydrogen production, even in non-polyhydroxyalkanoate-producing strains.

Enhanced theanine production with reduced ATP supply by alginate entrapped Escherichia coli co-expressing γ-glutamylmethylamide synthetase and polyphosphate kinase.

L-theanine is an amino acid with a unique flavor and many therapeutic effects. Its enzymatic synthesis has been actively studied and γ-Glutamylmethylamide synthetase (GMAS) is one of the promising enzymes in the biological synthesis of theanine. However, the theanine biosynthetic pathway with GMAS is highly ATP-dependent and the supply of external ATP was needed to achieve high concentration of theanine production. As a result, this study aimed to investigate polyphosphate kinase 2 (PPK2) as ATP regeneration system with hexametaphosphate. Furthermore, the alginate entrapment method was employed to immobilize whole cells containing both gmas and ppk2 together resulting in enhanced reusability of the theanine production system with reduced supply of ATP. After immobilization, theanine production was increased to 239 mM (41.6 g/L) with a conversion rate of 79.7% using 15 mM ATP and the reusability was enhanced, maintaining a 100% conversion rate up to the fifth cycles and 60% of conversion up to eighth cycles. It could increase long-term storage property for future uses up to 35 days with 75% activity of initial activity. Overall, immobilization of both production and cofactor regeneration system could increase the stability and reusability of theanine production system.

Microbial alchemy: upcycling of brewery spent grains into high-value products through fermentation.

Spent grains are one of the lignocellulosic biomasses available in abundance, discarded by breweries as waste. The brewing process generates around 25-30% of waste in different forms and spent grains alone account for 80-85% of that waste, resulting in a significant global waste volume. Despite containing essential nutrients, i.e., carbohydrates, fibers, proteins, fatty acids, lipids, minerals, and vitamins, efficient and economically viable valorization of these grains is lacking. Microbial fermentation enables the valorization of spent grain biomass into numerous commercially valuable products used in energy, food, healthcare, and biomaterials. However, the process still needs more investigation to overcome challenges, such as transportation, cost-effective pretreatment, and fermentation strategy. to lower the product cost and to achieve market feasibility and customer affordability. This review summarizes the potential of spent grains valorization via microbial fermentation and associated challenges.

Maximization of 3-hydroxyhexanoate fraction in poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) using lauric acid with engineered Cupriavidus necator H16.

As polyhydroxybutyrate (P(3HB)) was struggling with mechanical properties, efforts have been directed towards increasing mole fraction of 3-hydroxyhexanoate (3HHx) in P(3HB-co-3HHx) to improve the properties of polyhydroxyalkanoates (PHAs). Although genetic modification had significant results, there were several issues related to cell growth and PHA production by deletion of PHA synthetic genes. To find out easier strategy for high 3HHx mole fraction without gene deletion, Cupriavidus necator H16 containing phaC2Ra-phaACn-phaJ1Pa was examined with various oils resulting that coconut oil gave the highest 3HHx mole fraction. When fatty acid composition analysis with GC-MS was applied, coconut oil was found to have very different composition from other vegetable oil containing very high lauric acid (C12) content. To find out specific fatty acid affecting 3HHx fraction, different fatty acids from caproic acid (C6) to stearic acid (C18) was evaluated and the 3HHx mole fraction was increased to 26.5 ± 1.6 % using lauric acid. Moreover, the 3HHx mole fraction could be controlled from 9 % to 31.1 % by mixing bean oil and lauric acid with different ratios. Produced P(3HB-co-3HHx) exhibited higher molecular than P(3HB-co-3HHx) from phaB-deletion mutant. This study proposes another strategy to increase 3HHx mole fraction with easier way by modifying substrate composition without applying deletion tools.

Efficient polyhydroxybutyrate production using acetate by engineered Halomonas sp. JJY01 harboring acetyl-CoA acetyltransferase.

Polyhydroxybutyrate (PHB) is a well-known biodegradable bioplastic synthesized by microorganisms and can be produced from volatile fatty acids (VFAs). Among VFAs acetate can be utilized by Halomonas sp. YLGW01 for growth and PHB production. In this study, Halomonas sp. JJY01 was developed through introducing acetyl-CoA acetyltransferase (atoAD) with LacIq-Ptrc promoter into Halomonas sp. YLGW01. The effect of expression of atoAD on acetate was investigated by comparison with acetate consumption and PHB production. Shake-flask study showed that Halomonas sp. JJY01 increased acetate consumption rate, PHB yield and PHB production (0.27 g/L/h, 0.075 g/g, 0.72 g/L) compared to the wild type strain (0.17 g/L/h, 0.016 g/g, 0.11 g/L). In 10 L fermenter scale fed-batch fermentation, the growth of Halomonas sp. JJY01 resulted in higher acetate consumption rate, PHB yield and PHB titer (0.55 g/L/h, 0.091 g/g, 4.6 g/L) than wild type strain (0.35 g/L/h, 0.067 h/h, 2.9 g/L). These findings demonstrate enhanced acetate utilization and PHB production through the introduction of atoAD in Halomonas strains.

An efficient and eco-friendly approach for the sustainable recovery and properties characterization of polyhydroxyalkanoates produced by methanotrophs.

Synthetic biodegradable and bio-based polymers have emerged as sustainable alternatives to nonrenewable petroleum-derived polymers which cause serious environmental issues. In particular, polyhydroxyalkanoates (PHA) are promising biopolymers owing to their outstanding biodegradability and biocompatibility. The production of the homopolymer poly(3-hydroxybutyrate) (PHB) and copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) from type II methanotrophs via microbial fermentation was presented. For the efficient extraction and recovery of intracellular PHA from methanotrophs, different extraction approaches were investigated including solvent extraction using 1,3-dioxolane as a green solvent, integrated cell lysis and solvent extraction, and cell digestion without the use of organic solvents. Among various extraction approaches, the integrated method exhibited the highest extraction performance, with PHA recovery and purity exceeding 91 % and 93 %, respectively, even when the PHA content of the cells was low. Furthermore, the molecular weight, thermal stability, and mechanical properties of the recovered PHA were comprehensively analyzed to suggest its suitable practical applications. The obtained properties were comparable to that of the commercial PHA products and PHA produced from other microbial species, indicating an efficient recovery of high-quality PHA produced from methanotrophs.

Application of liquid-based colorimetric method for high throughput screening of bioplastic-degrading strains using esterase assay.

To alleviate environmental problems caused by using conventional plastics, bioplastics have garnered significant interest as alternatives to petroleum-based plastics. Despite possessing better degradability traits compared to traditional plastics, the degradation of bioplastics still demands a longer duration than initially anticipated. This necessitates the utilization of degradation strains or enzymes to enhance degradation efficiency, ensuring timely degradation. In this study, a novel screening method to identify bioplastic degraders faster was suggested to circumvent the time-consuming and laborious characteristics of solid-based plate assays. This liquid-based colorimetric method confirmed the extracellular esterase activity with p-nitrophenyl esters. It eliminated the needs to prepare plastic emulsion plates at the initial screening system, shortening the time for the overall screening process and providing more quantitative data. p-nitrophenyl hexanoate (C6) was considered the best substrate among the various p-nitrophenyl esters as substrates. The screening was performed in liquid-based 96-well plates, resulting in the discovery of a novel strain, Bacillus sp. SH09, with a similarity of 97.4% with Bacillus licheniformis. Furthermore, clear zone assays, degradation investigations, scanning electron microscopy, and gel permeation chromatography were conducted to characterize the biodegradation capabilities of the new strain, the liquid-based approach offered a swift and less labor-intensive option during the initial stages.

Unveiling the inhibition mechanism of Clostridioides difficile by Bifidobacterium longum via multiomics approach.

Antibiotic-induced gut microbiota disruption constitutes a major risk factor for Clostridioides difficile infection (CDI). Further, antibiotic therapy, which is the standard treatment option for CDI, exacerbates gut microbiota imbalance, thereby causing high recurrent CDI incidence. Consequently, probiotic-based CDI treatment has emerged as a long-term management and preventive option. However, the mechanisms underlying the therapeutic effects of probiotics for CDI remain uninvestigated, thereby creating a knowledge gap that needs to be addressed. To fill this gap, we used a multiomics approach to holistically investigate the mechanisms underlying the therapeutic effects of probiotics for CDI at a molecular level. We first screened Bifidobacterium longum owing to its inhibitory effect on C. difficile growth, then observed the physiological changes associated with the inhibition of C. difficile growth and toxin production via a multiomics approach. Regarding the mechanism underlying C. difficile growth inhibition, we detected a decrease in intracellular adenosine triphosphate (ATP) synthesis due to B. longum-produced lactate and a subsequent decrease in (deoxy)ribonucleoside triphosphate synthesis. Via the differential regulation of proteins involved in translation and protein quality control, we identified B. longum-induced proteinaceous stress. Finally, we found that B. longum suppressed the toxin production of C. difficile by replenishing proline consumed by it. Overall, the findings of the present study expand our understanding of the mechanisms by which probiotics inhibit C. difficile growth and contribute to the development of live biotherapeutic products based on molecular mechanisms for treating CDI.

Validating a Xylose Regulator to Increase Polyhydroxybutyrate Production for Utilizing Mixed Sugars from Lignocellulosic Biomass Using Escherichia coli.

Polyhydroxybutyrate (PHB) production from lignocellulosic biomass is economically beneficial. Because lignocellulosic biomass is a mixture rich in glucose and xylose, Escherichia coli, which prefers glucose, needs to overcome glucose repression for efficient biosugar use. To avoid glucose repression, here, we overexpressed a xylose regulator (xylR) in an E. coli strain expressing bktB, phaB, and phaC from Cupriavidus necator and evaluated the effect of xylR on PHB production. XylR overexpression increased xylose consumption from 0% to 46.53% and produced 4.45-fold more PHB than the control strain without xylR in a 1% sugar mixture of glucose and xylose (1:1). When the xylR over-expressed strain was applied to sugars from lignocellulosic biomass, cell growth and PHB production of the strain showed a 4.7-fold increase from the control strain, yielding 2.58 ± 0.02 g/l PHB and 4.43 ± 0.28 g/l dry cell weight in a 1% hydrolysate mixture. XylR overexpression increased the expression of xylose operon genes by up to 1.7-fold. Moreover, the effect of xylR was substantially different in various E. coli strains. Overall, the results showed the effect of xylR overexpression on PHB production in a non-native PHB producer and the possible application of xylR for xylose utilization in E. coli.

Production and characterization of a biodegradable polymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), using the type II methanotroph, Methylocystis sp. MJC1.

The production of polyhydroxyalkanoates (PHAs) through the biological conversion of methane is a promising solution to address both methane emissions and plastic waste. Type II methanotrophs naturally accumulate a representative PHA, poly(3-hydroxybutyrate) (PHB), using methane as the sole carbon source. In this study, we aimed to produce poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV copolymer) with improved properties compared with PHB, using the type II methanotroph, Methylocystis sp. MJC1. We optimized the pH, valerate concentration, and valerate supply time in a one-step cultivation process using a gas bioreactor to enhance PHBV copolymer production yield and the 3-hydroxyvalerate (3HV) molar fraction. Under the optimal conditions, the biomass reached 21.3 g DCW/L, and PHBV copolymer accumulation accounted for 41.9 % of the dried cell weight, with a 3HV molar fraction of 28.4 %. The physicochemical properties of the purified PHBV copolymer were characterized using NMR, FTIR, TGA, DSC, and GPC.

Production and engineering of nanobody-based quenchbody sensors for detecting recombinant human growth hormone and its isoforms.

Due to athletes' misuse of recombinant human growth hormone (rhGH) for performance improvement, the World Anti-Doping Agency has designated rhGH as a prohibited substance. This study focuses on the development and improvement of a simple and fast rhGH detection method using a fluorescence-incorporated antibody sensor "Quenchbody (Q-body)" that activates upon antigen binding. Camelid-derived nanobodies were used to produce stable Q-bodies that withstand high temperatures and pH levels. Notably, pituitary human growth hormone (phGH) comprises two major isoforms, namely 22 and 20 kDa GH, which exist in a specific ratio, and the rhGH variant shares the same sequence as the 22 kDa GH isoform. Therefore, we aimed to discriminate rhGH abuse by analyzing its specific isoform ratio. Two nanobodies, NbPit (recognizing phGH) and NbRec (preferentially recognizing 22 kDa rhGH), were used to develop the Q-bodies. Nanobody production in Escherichia coli involved the utilization of a vector containing 6xHis-tag, and Q-bodies were obtained using a maleimide-thiol reaction between the N-terminal of the cysteine tag and a fluorescent dye. The addition of tryptophan residue through antibody engineering resulted in increased fluorescence intensity (FI) (from 2.58-fold to 3.04-fold). The limit of detection (LOD) was determined using a fluorescence response, with TAMRA-labeled NbRec successfully detecting 6.38 ng/ml of 22 kDa rhGH while unable to detect 20 kDa GH. However, ATTO520-labeled NbPit detected 7.00 ng/ml of 20 kDa GH and 2.20 ng/ml 22 kDa rhGH. Q-bodies successfully detected changes in the GH concentration ratio from 10 to 40 ng/ml in human serum within 10 min without requiring specialized equipment and kits. Overall, these findings have potential applications in the field of anti-doping measures and can contribute to improved monitoring and enforcement of rhGH misuse, ultimately enhancing fairness and integrity in competitive sports.

Optimization of polyhydroxyalkanoate production in Halomonas sp. YLGW01 using mixed volatile fatty acids: a study on mixture analysis and fed-batch strategy.

Polyhydroxyalkanoate (PHA) is one of the most promising materials for replacing petroleum-based plastics, and it can be produced from various renewable biomass sources. In this study, PHA production was conducted using Halomonas sp. YLGW01 utilizing mixed volatile fatty acids (VFAs) as carbon sources. The ratio and concentration of carbon and nitrogen sources were optimized through mixture analysis and organic nitrogen source screening, respectively. It was found that the highest cell dry weight (CDW) of 3.15 g/L and PHA production of 1.63 g/L were achieved when the ratio of acetate to lactate in the mixed VFAs was 0.45:0.55. Furthermore, supplementation of organic nitrogen sources such as soytone resulted in a ninefold increase in CDW (reaching 2.32 g/L) and a 22-fold increase in PHA production (reaching 1.60 g/L) compared to using inorganic nitrogen sources. Subsequently, DO-stat, VFAs consumption rate stat, and pH-stat fed-batch methods were applied to investigate and evaluate PHA productivity. The results showed that when pH-stat-based VFAs feeding was employed, a CDW of 7 g/L and PHA production of 5.1 g/L were achieved within 68 h, with a PHA content of 73%. Overall, the pH-stat fed-batch strategy proved to be effective in enhancing PHA production by Halomonas sp. YLGW01 utilizing VFAs.

A strategy to promote the convenient storage and direct use of polyhydroxybutyrate-degrading Bacillus sp. JY14 by lyophilization with protective reagents.

BACKGROUND: Bioplastics are attracting considerable attention, owing to the increase in non-degradable waste. Using microorganisms to degrade bioplastics is a promising strategy for reducing non-degradable plastic waste. However, maintaining bacterial viability and activity during culture and storage remains challenging. With the use of conventional methods, cell viability and activity was lost; therefore, these conditions need to be optimized for the practical application of microorganisms in bioplastic degradation. Therefore, we aimed to optimize the feasibility of the lyophilization method for convenient storage and direct use. In addition, we incoporated protective reagents to increase the viability and activity of lyophilized microorganisms. By selecting and applying the best protective reagents for the lyophilization process and the effects of additives on the growth and PHB-degrading activity of strains were analyzed after lyophilization. For developing the lyophilization method for protecting degradation activity, it may promote practical applications of bioplastic-degrading bacteria. RESULTS: In this study, the polyhydroxybutyrate (PHB)-degrading strain, Bacillus sp. JY14 was lyophilized with the use of various sugars as protective reagents. Among the carbon sources tested, raffinose was associated with the highest cell survival rate (12.1%). Moreover, 7% of raffionose showed the highest PHB degradation yield (92.1%). Therefore, raffinose was selected as the most effective protective reagent. Also, bacterial activity was successfully maintained, with raffinose, under different storage temperatures and period. CONCLUSIONS: This study highlights lyophilization as an efficient microorganism storage method to enhance the applicability of bioplastic-degrading bacterial strains. The approach developed herein can be further studied and used to promote the application of microorganisms in bioplastic degradation.

Enhanced production of glutaric acid by biocatalyst-recycled bioconversion process integrated with in situ product recovery by adsorption.

Product inhibition caused by organic acids is a serious issue in establishing economical biochemical production systems. Herein, for enhanced production of glutaric acid by overcoming product inhibition triggered by glutaric acid, a whole-cell bioconversion system equipped with biocatalyst recycling process and in situ product recovery by adsorption was developed successfully. From the whole-cell bioconversion reaction, we found that both dissociated and undissociated forms of glutaric acid acted as an inhibitor in the whole-cell bioconversion reaction, wherein bioconversion was hindered beyond 200 mM glutaric acid regardless of reaction pH. Therefore, as the promising solution for the inhibition issue by glutaric acid, the biocatalyst-recycled bioconversion process integrated with in situ product recovery by adsorption was introduced in the whole-cell bioconversion. As a result, 592 mM glutaric acid was produced from 1000 mM 5-aminovaleric acid with 59.2% conversion. We believe that our system will be a promising candidate for economically producing organic acids with high titer.