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Fermentative polyhydroxybutyrate production from a novel feedstock derived from bakery waste.

Pleissner D, Lam WC, Han W, Lau KY, Cheung LC, Lee MW, Lei HM, Lo KY, Ng WY, Sun Z, Melikoglu M, Lin CS - Biomed Res Int (2014)

Bottom Line: These include: (1) use of crude enzyme extracts from Aspergillus awamori, (2) Aspergillus awamori solid mashes, and (3) commercial glucoamylase.In both cases, the final glucose concentration was around 130-150 g L(-1).The present work has generated promising information contributing to the sustainable production of bioplastic using bakery waste hydrolysate.

View Article: PubMed Central - PubMed

Affiliation: School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong.

ABSTRACT
In this study, Halomonas boliviensis was cultivated on bakery waste hydrolysate and seawater in batch and fed-batch cultures for polyhydroxybutyrate (PHB) production. Results demonstrated that bakery waste hydrolysate and seawater could be efficiently utilized by Halomonas boliviensis while PHB contents between 10 and 30% (w/w) were obtained. Furthermore, three methods for bakery waste hydrolysis were investigated for feedstock preparation. These include: (1) use of crude enzyme extracts from Aspergillus awamori, (2) Aspergillus awamori solid mashes, and (3) commercial glucoamylase. In the first method, the resultant free amino nitrogen (FAN) concentration in hydrolysates was 150 and 250 mg L(-1) after 20 hours at enzyme-to-solid ratios of 6.9 and 13.1 U g(-1), respectively. In both cases, the final glucose concentration was around 130-150 g L(-1). In the second method, the resultant FAN and glucose concentrations were 250 mg L(-1) and 150 g L(-1), respectively. In the third method, highest glucose and lowest FAN concentrations of 170-200 g L(-1) and 100 mg L(-1), respectively, were obtained in hydrolysates after only 5 hours. The present work has generated promising information contributing to the sustainable production of bioplastic using bakery waste hydrolysate.

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Change in glucose and FAN concentrations in hydrolysate during bakery waste hydrolysis using a crude enzyme extract from Aspergillus awamori solid mashes ((a) and (b)), Aspergillus awamori solid mashes directly added ((c) and (d)), commercial glucoamylase ((e) and (f)), and in a control ((g) and (h)), respectively. Hydrolyses carried out using crude enzyme extract and commercial glucoamylase were performed at enzyme-to-solid ratios of 6.9 and 13.1 U g−1.
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fig2: Change in glucose and FAN concentrations in hydrolysate during bakery waste hydrolysis using a crude enzyme extract from Aspergillus awamori solid mashes ((a) and (b)), Aspergillus awamori solid mashes directly added ((c) and (d)), commercial glucoamylase ((e) and (f)), and in a control ((g) and (h)), respectively. Hydrolyses carried out using crude enzyme extract and commercial glucoamylase were performed at enzyme-to-solid ratios of 6.9 and 13.1 U g−1.

Mentions: Firstly, bakery waste hydrolysis was carried out using crude enzyme extracts from Aspergillus awamori solid mashes at enzyme-to-solid ratios of 6.9 and 13.1 U g−1. In both cases, similar glucose concentrations of 130–150 g L−1 were found in hydrolysates after 20 hours (Figure 2(a)). However, the resultant FAN concentrations showed significant difference (Table 3, Figure 2(b)). When hydrolysis was performed at 6.9 U g−1, 150 mg L−1 of FAN was obtained. When the enzyme-to-solid ratio was increased to 13.1 U g−1 by addition of a larger volume of crude enzyme extract, the FAN concentration also increased to 250 mg L−1. Aspergillus awamori is known for the secretion of both glycolytic and to a lesser extent of proteolytic enzymes [22]. Therefore, the addition of a larger volume of the crude enzyme extract led not only to increased initial glycolytic activity, but also proteolytic activity (data not shown) and consequently to higher FAN concentration in hydrolysate. This finding highlighted the possibility to adjust the resultant FAN concentration using crude enzyme extract in order to prepare a fermentation feedstock which is favourable for promoting biomass formation, while the glucose concentration remains unaffected. Figures 2(c) and 2(d) show the glucose and FAN production profiles when hydrolysis was carried out using Aspergillus awamori solid mashes. The final glucose and FAN concentrations were similar to the concentrations obtained after hydrolysis of bakery waste carried out at an enzyme-to-solid ratio of 13.1 U g−1 (Figures 2(a) and 2(b)). Thus, there is no need to extract enzymes from fungal solid mashes prior to the use in hydrolysis.


Fermentative polyhydroxybutyrate production from a novel feedstock derived from bakery waste.

Pleissner D, Lam WC, Han W, Lau KY, Cheung LC, Lee MW, Lei HM, Lo KY, Ng WY, Sun Z, Melikoglu M, Lin CS - Biomed Res Int (2014)

Change in glucose and FAN concentrations in hydrolysate during bakery waste hydrolysis using a crude enzyme extract from Aspergillus awamori solid mashes ((a) and (b)), Aspergillus awamori solid mashes directly added ((c) and (d)), commercial glucoamylase ((e) and (f)), and in a control ((g) and (h)), respectively. Hydrolyses carried out using crude enzyme extract and commercial glucoamylase were performed at enzyme-to-solid ratios of 6.9 and 13.1 U g−1.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4127261&req=5

fig2: Change in glucose and FAN concentrations in hydrolysate during bakery waste hydrolysis using a crude enzyme extract from Aspergillus awamori solid mashes ((a) and (b)), Aspergillus awamori solid mashes directly added ((c) and (d)), commercial glucoamylase ((e) and (f)), and in a control ((g) and (h)), respectively. Hydrolyses carried out using crude enzyme extract and commercial glucoamylase were performed at enzyme-to-solid ratios of 6.9 and 13.1 U g−1.
Mentions: Firstly, bakery waste hydrolysis was carried out using crude enzyme extracts from Aspergillus awamori solid mashes at enzyme-to-solid ratios of 6.9 and 13.1 U g−1. In both cases, similar glucose concentrations of 130–150 g L−1 were found in hydrolysates after 20 hours (Figure 2(a)). However, the resultant FAN concentrations showed significant difference (Table 3, Figure 2(b)). When hydrolysis was performed at 6.9 U g−1, 150 mg L−1 of FAN was obtained. When the enzyme-to-solid ratio was increased to 13.1 U g−1 by addition of a larger volume of crude enzyme extract, the FAN concentration also increased to 250 mg L−1. Aspergillus awamori is known for the secretion of both glycolytic and to a lesser extent of proteolytic enzymes [22]. Therefore, the addition of a larger volume of the crude enzyme extract led not only to increased initial glycolytic activity, but also proteolytic activity (data not shown) and consequently to higher FAN concentration in hydrolysate. This finding highlighted the possibility to adjust the resultant FAN concentration using crude enzyme extract in order to prepare a fermentation feedstock which is favourable for promoting biomass formation, while the glucose concentration remains unaffected. Figures 2(c) and 2(d) show the glucose and FAN production profiles when hydrolysis was carried out using Aspergillus awamori solid mashes. The final glucose and FAN concentrations were similar to the concentrations obtained after hydrolysis of bakery waste carried out at an enzyme-to-solid ratio of 13.1 U g−1 (Figures 2(a) and 2(b)). Thus, there is no need to extract enzymes from fungal solid mashes prior to the use in hydrolysis.

Bottom Line: These include: (1) use of crude enzyme extracts from Aspergillus awamori, (2) Aspergillus awamori solid mashes, and (3) commercial glucoamylase.In both cases, the final glucose concentration was around 130-150 g L(-1).The present work has generated promising information contributing to the sustainable production of bioplastic using bakery waste hydrolysate.

View Article: PubMed Central - PubMed

Affiliation: School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong.

ABSTRACT
In this study, Halomonas boliviensis was cultivated on bakery waste hydrolysate and seawater in batch and fed-batch cultures for polyhydroxybutyrate (PHB) production. Results demonstrated that bakery waste hydrolysate and seawater could be efficiently utilized by Halomonas boliviensis while PHB contents between 10 and 30% (w/w) were obtained. Furthermore, three methods for bakery waste hydrolysis were investigated for feedstock preparation. These include: (1) use of crude enzyme extracts from Aspergillus awamori, (2) Aspergillus awamori solid mashes, and (3) commercial glucoamylase. In the first method, the resultant free amino nitrogen (FAN) concentration in hydrolysates was 150 and 250 mg L(-1) after 20 hours at enzyme-to-solid ratios of 6.9 and 13.1 U g(-1), respectively. In both cases, the final glucose concentration was around 130-150 g L(-1). In the second method, the resultant FAN and glucose concentrations were 250 mg L(-1) and 150 g L(-1), respectively. In the third method, highest glucose and lowest FAN concentrations of 170-200 g L(-1) and 100 mg L(-1), respectively, were obtained in hydrolysates after only 5 hours. The present work has generated promising information contributing to the sustainable production of bioplastic using bakery waste hydrolysate.

Show MeSH