Synergistic optimization of baffles and aeration to improve the Light/Dark cycle of microalgae photobioreactor for enhanced nitrogen removal performance: Computational fluid dynamics and experimental verification.

Microalgae photobioreactor (PBR) is a kind of efficient wastewater treatment system for nitrogen removal. However, there is still an urgent need for process optimization of PBR. Especially, the synergistic effect and optimization of light and flow state poses a challenge. In this study, the computational fluid dynamics is employed for simulating the optimization of the number and length of the internal baffles, as well as the aeration rate of PBR, which in turn leads to the optimal growth of microalgae and efficient nitrogen removal. After optimization, the Light/Dark cycle of the reactor B is shortened by 51.6 %, and the biomass increases from 0.06 g/L to 3.94 g/L. In addition, the removal rate of NH4+-N increased by 106.0 % to 1.56 mg L-1 h-1. This work provides a feasible method for optimizing the design and operational parameters of PBR aiming the engineering application.

Bidirectional Enhancement of Nitrogen Removal by Indigenous Synergetic Microalgal-Bacterial Consortia in Harsh Low-C/N Wastewater.

Conventional microalgal-bacterial consortia have limited capacity to treat low-C/N wastewater due to carbon limitation and single nitrogen (N) removal mode. In this work, indigenous synergetic microalgal-bacterial consortia with high N removal performance and bidirectional interaction were successful in treating rare earth tailing wastewaters with low-C/N. Ammonia removal reached 0.89 mg N L-1 h-1, 1.84-fold more efficient than a common microalgal-bacterial system. Metagenomics-based metabolic reconstruction revealed bidirectional microalgal-bacterial interactions. The presence of microalgae increased the abundance of bacterial N-related genes by 1.5- to 57-fold. Similarly, the presence of bacteria increased the abundance of microalgal N assimilation by 2.5- to 15.8-fold. Furthermore, nine bacterial species were isolated, and the bidirectional promotion of N removal by the microalgal-bacterial system was verified. The mechanism of microalgal N assimilation enhanced by indole-3-acetic acid was revealed. In addition, the bidirectional mode of the system ensured the scavenging of toxic byproducts from nitrate metabolism to maintain the stability of the system. Collectively, the bidirectional enhancement system of synergetic microalgae-bacteria was established as an effective N removal strategy to broaden the stable application of this system for the effective treatment of low C/N ratio wastewater.

Clostridium aromativorans sp. nov., isolated from pit mud used for producing Wuliangye baijiu.

A strictly anaerobic, gram-positive bacterium, designated as WLY-B-L2T, was isolated from pit mud of a fermentation pit located at Wuliangye 501# baijiu workshop in Yibin (Sichuan province, PR China). The strain was strictly anaerobic, Gram-positive with straight or somewhat rod shaped cells which were 0.5-0.7 µm wide and 1.7-3.1 µm long, arranged singly or in pairs. The strain can utilize D-galacturonic acid, methyl pyruvate, L-lactamine, L-alanyl - L-glutamine, L-alanyl - L-histidine, glycerol, pyruvate, L-alanyl - L-threonine, L-methionine, L-phenylalanine, L-valine + L-aspartic acid, L-serine, L-valine, and thymidine as carbon sources. Major cellular fatty acids are C16: 0 (24.6%), anteiso-C15: 0 (16.5%), and iso-C15: 0 (14.1%). Based on 16S rRNA gene sequence, WLY-B-L2T is most closely related to Clostridium luticellarii FW431T; they exhibit 97.42% 16S rRNA similarity. Additionally, the digital DNA-DNA hybridization (dDDH) value between them is 28.10%. WLY-B-L2T has a G + C content of 34.16 mol%. Based on the evidence presented here, WLY-B-L2T (CICC 25133T = JCM 35127T) is proposed as the type strain of a novel species, designated as Clostridium aromativorans sp. nov, that could produce butyric acid and volatile flavor components, such as ethyl valerate, ethyl acetate and 2-pentanone.

Rapid Test Method for Multi-Beam Profile of Phased Array Antennas.

The measurement of the phased array antenna (PAA) is completely different from the traditional antenna, due to its multi beam patterns. Usually, each beam pattern of the PAA needs a separate measurement, which makes the overall time extremely long. Thus, the traditional method can no longer meet the efficiency and cost requirements of new PAA measurement. In this paper, a pattern reconstruction method is proposed which significantly reduce the measurement time of multi-beam PAAs. With the known array element patterns (AEP) and theoretical weighted port excitation of the beams, any beam pattern can be predicted by measuring only a certain beam pattern, due to the element excitation coefficient (including the matching, mutual coupling, and manufacturing factors, etc.) of the specific PAA being calculated. The approach has low reconstruction error in term of beam pointing accuracy, side lobe, and co-polar and cross-polar patterns while being validated for large scanning range. Through theoretical derivation and experiments, the effectiveness of the method is verified, and the testing efficiency of the phased array antenna can be improved by 10 times or even more.

Assessment of ß-glucans, phenols, flavor and volatile profiles of hulless barley wine originating from highland areas of China.

Low alcohol hulless barley wine (HW) is a popular beverage among the highland areas in China. It is known to have several health benefits due to the presence of ß-glucan and antioxidant compounds. Therefore, the total ß-glucan content, total phenols and flavonoids of HW samples from the highland areas of Sichuan province and Tibet were determined in this study. The results indicated that HW is abundant in both ß-glucan (54-76 mg/L) and phenolic compounds (131-178 mg/L). Moreover, this study also investigated the flavor and aroma characteristics of HW samples. A total of forty six volatile aroma substances were identified by GC-MS. The HWs could be classified into three distinct groups in terms of the region of origin according to the results of PCA based on the GC-MS data. These findings provide a useful foundation for further study of the health benefits and the flavor characteristics of HW in highland areas.

Analysis of the bacterial community in aged and aging pit mud of Chinese Luzhou-flavour liquor by combined PCR-DGGE and quantitative PCR assay.

BACKGROUND: The community structure of bacteria in aged and aging pit mud, which was judged according to their sensory and physicochemical characteristics, was analysed using polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) and quantitative real-time PCR (qPCR). RESULTS: The phyla Firmicutes, Actinobacteria, Proteobacteria, Synergistetes and Unclassified Bacteria were detected and the fermentative Firmicutes was predominant in both types of pit mud in the PCR-DGGE analysis. Among Firmicutes, Clostridiales was dominant in aged pit mud while Bacillales and Lactobacillales were dominant in aging pit mud. The diversity of bacterial communities in aged pit mud was higher than that in aging pit mud. In the qPCR analysis the abundance of Clostridium IV in aged pit mud was higher than that in aging pit mud and there were significant differences in the quantity of Clostridium IV between aged and aging pit mud of the same cellar (P < 0.05). CONCLUSION: There were some significant differences in the microbial community structure between aged and aging pit mud. The differences in the quantity of Clostridium IV might be involved in the distinction that the aged pit mud has a strong aroma while the aging pit mud does not.