“…Also, absence of the 1.6 and 0.9 shifts representing C4 (-CH 2 group of 3HV) and C5 (-CH 3 group of 3HV), respectively [39], [41] confirmed the nature of the enzymatically extracted polymer to be a pure homopolymer of poly (3-hyroxybutyrate) or P3HB. The 1 H NMR spectrum obtained was also well in agreement with the earlier reports of homopolymer P3HB accumulation by B. megaterium Ti3 on glucose as a carbon source [27], [28] thus validating the extracted material as a polyhydroxyalkanoate of P3HB type.Fig. 10 1 H NMR spectrum of the polymer extracted from B. megaterium Ti3.…”
Section: Resultssupporting
confidence: 89%
“…PHA producer Bacillus megaterium strain Ti3 was used in the present study [26]. The strain was maintained on nutrient agar plates at 4 °C.…”
Section: Methodsmentioning
confidence: 99%
“…The strain was maintained on nutrient agar plates at 4 °C. The strain accumulates PHA during growth phase with a maximum yield of 0.6 g/L amounting to 44.1 ± 0.9% accumulation [27].…”
Section: Methodsmentioning
confidence: 99%
“…Production studies were carried out in 250 mL Erlenmeyer flasks containing 100 mL culture medium. Incubation was done at 30 °C, 120 rpm for 24 h [27]. After incubation, the biomass content or cell dry mass (CDM) was evaluated by gravimetry.…”
The applicability of Streptomyces sp. cell lytic enzymes for devising a simple and competent biological polyhydroxyalkanoate (PHA) recovery approach from Bacillus megaterium cells was investigated. B. megaterium strain Ti3 produced 50% (w/w) PHA using glucose as carbon source. The intracellular PHA was recovered employing a non-PHA accumulating actinomycetes (Tia1) identified as Streptomyces albus, having potent lytic activity against living and heat inactivated B. megaterium. Interestingly, maximum biomass (2.53 ± 0.6 g/L by 24 h) of the lytic actinomycete was obtained in PHA production medium itself thus circumventing the prior actinomycete acclimatization just by co-inoculation with B. megaterium as an inducer. Maximum lytic activity was observed at pH 6.0, 40 °C, 220 mg of biomass and 33.3 mL of concentrated culture filtrate in a 100 mL reaction mixture. Preliminary biochemical investigations confirmed the proteolytic and caseinolytic nature of the lytic enzyme. PHA yield of 0.55 g/g by co-inoculation extraction approach was comparable with the conventional sodium hypochlorite based extraction method. Interestingly, S. albus also demonstrated a broad spectrum lytic potential against varied Gram-negative and Gram-positive PHA producers highlighting the extensive applicability of this biolytic PHA recovery approach. The lytic enzyme retained almost 100% relative activity on storage at −20 °C upto two months. 1H Nuclear magnetic resonance analysis of the extracted polymer confirmed it as a homopolymer composed of 3-hydroxybutyrate monomeric units. This is the first report on Streptomyces sp. based biological and eco-friendly, intracellular PHA recovery from Bacillus spp.
“…Also, absence of the 1.6 and 0.9 shifts representing C4 (-CH 2 group of 3HV) and C5 (-CH 3 group of 3HV), respectively [39], [41] confirmed the nature of the enzymatically extracted polymer to be a pure homopolymer of poly (3-hyroxybutyrate) or P3HB. The 1 H NMR spectrum obtained was also well in agreement with the earlier reports of homopolymer P3HB accumulation by B. megaterium Ti3 on glucose as a carbon source [27], [28] thus validating the extracted material as a polyhydroxyalkanoate of P3HB type.Fig. 10 1 H NMR spectrum of the polymer extracted from B. megaterium Ti3.…”
Section: Resultssupporting
confidence: 89%
“…PHA producer Bacillus megaterium strain Ti3 was used in the present study [26]. The strain was maintained on nutrient agar plates at 4 °C.…”
Section: Methodsmentioning
confidence: 99%
“…The strain was maintained on nutrient agar plates at 4 °C. The strain accumulates PHA during growth phase with a maximum yield of 0.6 g/L amounting to 44.1 ± 0.9% accumulation [27].…”
Section: Methodsmentioning
confidence: 99%
“…Production studies were carried out in 250 mL Erlenmeyer flasks containing 100 mL culture medium. Incubation was done at 30 °C, 120 rpm for 24 h [27]. After incubation, the biomass content or cell dry mass (CDM) was evaluated by gravimetry.…”
The applicability of Streptomyces sp. cell lytic enzymes for devising a simple and competent biological polyhydroxyalkanoate (PHA) recovery approach from Bacillus megaterium cells was investigated. B. megaterium strain Ti3 produced 50% (w/w) PHA using glucose as carbon source. The intracellular PHA was recovered employing a non-PHA accumulating actinomycetes (Tia1) identified as Streptomyces albus, having potent lytic activity against living and heat inactivated B. megaterium. Interestingly, maximum biomass (2.53 ± 0.6 g/L by 24 h) of the lytic actinomycete was obtained in PHA production medium itself thus circumventing the prior actinomycete acclimatization just by co-inoculation with B. megaterium as an inducer. Maximum lytic activity was observed at pH 6.0, 40 °C, 220 mg of biomass and 33.3 mL of concentrated culture filtrate in a 100 mL reaction mixture. Preliminary biochemical investigations confirmed the proteolytic and caseinolytic nature of the lytic enzyme. PHA yield of 0.55 g/g by co-inoculation extraction approach was comparable with the conventional sodium hypochlorite based extraction method. Interestingly, S. albus also demonstrated a broad spectrum lytic potential against varied Gram-negative and Gram-positive PHA producers highlighting the extensive applicability of this biolytic PHA recovery approach. The lytic enzyme retained almost 100% relative activity on storage at −20 °C upto two months. 1H Nuclear magnetic resonance analysis of the extracted polymer confirmed it as a homopolymer composed of 3-hydroxybutyrate monomeric units. This is the first report on Streptomyces sp. based biological and eco-friendly, intracellular PHA recovery from Bacillus spp.
“…Nonetheless, in the vast majority of the publications, PHB has been used along with natural polymers. 4,5 The purpose of this combination is to increase hydrophilicity, improve degradation rate, reduce brittleness, and especially develop the mechanical properties of PHB. 6 Among natural polymers, lignin has been used along with other polymers such as polyvinyl alcohol, polycaprolactone, starch, and so forth.…”
Over the past decades, limited strategies have been developed to study nanomechanical properties. The in-depth study on the nanomechanical properties of electrospun scaffolds can provide better insights at greater scales. Atomic force microscopy (AFM) nanoindentation is an authoritative method that can characterize mechanical properties. In this research, theoretical solubility studies of polyhydroxybutyrate (PHB) in different solvents were initially carried out. Then, three series of PHB-based mats were prepared, including PHB/lignin, PHB/cellulose nanofiber (CNF), and PHB/lignin/CNF. The theoretical modulus of samples was studied from two different standpoints, through the use of nanoindentation on a single nanofiber. First, scaffolds were considered as a series of short fiber reinforced nanocomposites (NCs). In the second viewpoint, the geometrical structure of each scaffold was considered similar to an open-cell foam (OCF). Consequently, modeling outputs verified that among NC models, isotropic Halpin-Tsai presented plausible predictions with '93.36 to 99.77% accuracy. In addition, Tetrakaidecahedron indicated more accurate predictions among OCF models for the mats ('78.99 to 96.15% adaption). Indeed, the theoretical NC and OCF models were able to provide acceptable forecasts for the application range of electrospun fibers. Based on this, nanoscale investigation of mechanical properties can turn a new page to estimate the further application of mats.
Poly(3-hydroxybutyrate) (PHB) is a microbially produced biopolymer that is emerging as a propitious alternative to petroleum-based plastics owing to its biodegradable and biocompatible properties. However, to date, the relatively high costs related to the PHB production process are hampering its widespread commercialization. Since feedstock costs add up to half of the total production costs, ample research has been focusing on the use of inexpensive industrial side streams as carbon sources. While various industrial side streams such as second-generation carbohydrates, lignocellulose, lipids, and glycerol have been extensively investigated in liquid fermentation processes, also gaseous sources, including carbon dioxide, carbon monoxide, and methane, are gaining attention as substrates for gas fermentation. In addition, recent studies have investigated two-stage processes to convert waste gases into PHB via organic acids or alcohols. In this review, a variety of different industrial side streams are discussed as more sustainable and economical carbon sources for microbial PHB production. In particular, a comprehensive overview of recent developments and remaining challenges in fermentation strategies using these feedstocks is provided, considering technical, environmental, and economic aspects to shed light on their industrial feasibility. As such, this review aims to contribute to the global shift towards a zero-waste bio-economy and more sustainable materials.
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