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The Structure of the Cannibal Sludge flocs generated under the fast and the slow feed conditions and their Digestibility
(2024-06-01)
Khanthongthip, Passkorn
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Novak, John T.
An activated sludge system that incorporates a sidestream anaerobic bioreactor, called the Cannibal process, generated about 60 % less solids than conventional activated sludge without any negative effects on the effluent quality. In addition, operating the Cannibal process with different feeding patterns can result in different system performance. When the feed is provided to the Cannibal system over a period of 5 minutes (fast feed), the system generates less solid than the Cannibal system fed over a period of 4 hours (slow feed). In this study, the cation exchange resin (CER) and sulfide addition procedures were utilized to extract the Cannibal sludge flocs generated under the fast and the slow feed conditions to gain a fundamental insight on the structure and their components of those flocs. In addition, the fast and the slow feed Cannibal sludge was anaerobically and aerobically digested to evaluate the effect of feeding patterns on their digestibility. It was found that the readily biodegradable (1 kDa.) CER and sulfide extracted protein is larger in the flocs from the fast feed than the slow feed Cannibal system. When these two different types of flocs were anaerobically digested, the major fractions to be degraded were the sulfide extractable proteins. It was also found that the proteins in the fast feed Cannibal sludge flocs were degraded more than that in the slow feed Cannibal sludge flocs under anaerobic conditions. Consequently, it can be proposed that the influence of the high substrate pressure (fast feed) is to generate larger readily biodegradable proteins in the fast feed than the slow feed Cannibal sludge flocs. Because the 1 kDa. sulfide extracted proteins released from the fast feed Cannibal sludge floc are more biodegradable than that from the slow feed Cannibal sludge under anaerobic environment, it can be thought that the 1 kDa. proteins generated under the fast feed condition may consist of either many simple amino acids that are easily degradable or amino acids that microorganisms cannot produce but need to consume for their survival.
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Pressurized hot water extraction of crude polysaccharides, β-glucan, and phenolic compounds from dried gray oyster mushroom
(2022-10-01)
Sakdasri, Winatta
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Arnutpongchai, Panisara
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Phonsavat, Supasuta
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Bumrungthaichaichan, Eakarach
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Sawangkeaw, Ruengwit
This study aimed to investigate the effects of temperature (100 °C–140 °C), pressure (0.4–1.0 MPa), and extraction time (20–60 min) on the extraction yield of crude polysaccharides, β-glucan, and total phenolic compounds with pressurized hot water extraction of gray oyster mushrooms (Pleurotus sajor-caju (Fr.) Singer). The extraction conditions were optimized by maximizing all responses, using a central composite design (CCD)-based response surface methodology. Temperature mainly affected the increase in the extracted yield and phenolic content. However, exceeded temperature and extraction time negatively affected the β-glucan yield. The optimal extraction conditions were at 140 °C, 0.92 MPa, and 40 min with a corresponding extraction yield of 3.20 ± 0.17 g/100 g, as well as β-glucan and total phenolic contents of 43.84 ± 3.86 mg/100 g and 8.49 ± 0.66 mg gallic acid equivalent/100 g dried extract, respectively. The antioxidant activities of extracts were estimated by in vitro biological assays. The SC<inf>50</inf> values of DPPH, NO, and ABTS assays were 1.66 ± 0.02, 1.50 ± 0.19, and 6.94 ± 1.04 mg/mL, respectively. This work demonstrates an alternative approach to valorize over-produced mushrooms.
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Effects of low pH and Pb2+ stress on living cyanobacterium, Phormidium angustissimum West & G.S.West: A test of its feasibility as a living biosorbent
(2013-06-01)
Ruangsomboon, Suneerat
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Wongrat, Ladda
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Choochote, Sakchai
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Ganmanee, Monthon
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Saparnklang, Atiya
Pb2+ adsorption by the living cyanobacterium, Phormidium angustissimum followed the Langmuir adsorption model, with the maximum adsorption capacity (q <inf>max</inf>) of 295.4 ± 13.8 mg g-1. This result suggests that P. angustissimum is a promising living biosorbent to remove Pb2+ from wastewaters. Living biosorbents are better able to remove Pb2+ from wastewater than dead biosorbents, however there are practical limitations for their use are encountered in extreme conditions such as low pH and high Pb2+ concentration. The feasibility of using cyanobacterium, P. angustissimum, as a living biosorbent for the extraction of Pb2+ from wastewater was studied by investigating its photosynthestic performance and tolerance under Pb2+ (0-5 mg L-1) contamination and low pH (pH 3-7). Decreased photosynthetic performance caused by Pb2+ contamination and low pH stress was detected in this study by means of a reduction of the maximum photochemical efficiency of PSII (F<inf>v</inf>/F<inf>m</inf>). Detoxification mechanisms of P. angustissimum on Pb2+ appeared to increase its intracellular polysaccharides (IPS), exocellular polysaccharides (EPS), and protein. Living P. angustissimum could increase the pH of the solution which resulted in Pb2+ precipitation. The unique ability of P. angustissimum to remove Pb2+ and to grow under toxic conditions, demonstrated herein, indicates that it is a promising living biosorbent for mildly acidic water contaminated with Pb2+ in bioremoval systems in the which pH is not lower than 5 and Pb2+ is not higher than 5 mg L-1. © 2013 Springer Science+Business Media Dordrecht.

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