This paper reports the effects of changing pH (5-7) and temperature (T, 40-60 degrees C) on the efficiencies of bacterial hydrolysis of suspended organic matter (SOM) in wastewater from food waste recycling (FWR) and the changes in the bacterial community responsible for this hydrolysis. Maximum hydrolysis efficiency (i.e., 50.5% reduction of volatile suspended solids) was predicted to occur at pH 5.7 and T = 44.5 degrees C. Changes in short-chain volatile organic acid profiles and in acidogenic bacterial communities were investigated under these conditions. Propionic and butyric acids concentrations increased rapidly during the first 2 days of incubation. Several band sequences consistent with Clostridium spp. were detected using denaturing gel gradient electrophoresis. Clostridium thermopalmarium and Clostridium novyi seemed to contribute to butyric acid production during the first 1.5 days of acidification of FWR wastewater, and C. thermopalmarium was a major butyric acid producer afterward. C. novyi was an important propionic acid producer. These two species appear to be important contributors to hydrolysis of SOM in the wastewater. Other acidogenic anaerobes, Aeromonas sharmana, Bacillus coagulans, and Pseudomonas plecoglossicida, were also indentified.

Taxonomic studies were performed on an agarase-producing strain, designated WV33 T , isolated from faeces of Antarctic penguins. Cells of strain WV33 T were Gram-staining-negative, strictly aerobic, orange and rod-shaped. Strain WV33 T displayed agarase activity and was able to utilize galactose as a sole carbon source. 16S rRNA gene sequence analysis revealed that strain WV33 T was closely related to Flavobacterium algicola TC2 T (98.0 % similarity), F. frigidarium ATCC 700810 T (96.9 %) and F. frigoris LMG 21922 T (96.1 %). The predominant cellular fatty acids were iso-C 15 : 1 G, iso-C 15 : 0 , C 15 : 0 , C 16 : 0 and summed feature 3 (comprising iso-C 15 : 0 2-OH and/or C 16 : 1 v7c). Menaquinone 6 (MK-6) was the sole quinone identified, and the major pigment was zeaxanthin. The major polar lipid was phosphatidylethanolamine. DNA-DNA relatedness of strain WV33 T with respect to its closest phylogenetic neighbours was 25 % for F. algicola NBRC 102673 T , 23 % for F. frigidarium DSM 17623 T and 21 % for F. frigoris DSM 15719 T . The DNA G+C content of strain WV33 T was 37±0.6 mol%. Based on the phenotypic, chemotaxonomic and phylogenetic data, strain WV33 T is concluded to represent a novel species of the genus Flavobacterium, for which the name Flavobacterium faecale sp. nov. is proposed. The type strain is WV33 T (5KCTC 32457 T 5CECT 8384 T ).

The effects of hydraulic retention time (HRT), pH, and operating temperature (T ) on the degradation of food waste-recycling wastewater (FRW) were investigated in laboratory-scale hydrolysis/acidogenesis reactors. Response surface analysis was used to approximate the production of volatile organic acids and degradation of volatile suspended solids (VSS), carbohydrate, protein, and lipid with regard to the independent variables (1 ≤ HRT ≤ 3 days, 4 ≤ pH ≤ 6, 25 ≤ T ≤ 45 °C). Partial cubic models adequately approximated the corresponding response surfaces at α < 5 %. The physiological conditions for maximum acidification (0.4 g TVFA + EtOH/g VS) and the maximal degradation of VSS (47.5 %), carbohydrate (92.0 %), protein (17.7 %), and lipid (73.7 %) were different. Analysis of variance suggested that pH had a great effect on the responses in most cases, while T and HRT, and their interaction, were significant in some cases. Denaturing gradient gel electrophoresis analysis revealed that Sporanaerobacter acetigenes, Lactobacillus sp., and Eubacterium pyruvivorans-like microorganisms might be main contributors to the hydrolysis and acidogenesis of FRW. Biochemical methane potential test confirmed higher methane yield (538.2 mL CH/g VS) from an acidogenic effluent than from raw FRW.

Background Chemical fertilizers have greatly contributed to the development of agriculture, but alternative fertilizers are needed for the sustainable development of agriculture. 2,3-butanediol (2,3-BDO) is a promising biological plant growth promoter. Results In this study, we attempted to develop an effective strategy for the biological production of highly pure R,R-2,3-butanediol (R,R-2,3-BDO) by Paenibacillus polymyxa fermentation. First, gamma-ray mutagenesis was performed to obtain P. polymyxa MDBDO, a strain that grew faster than the parent strain and had high production of R,R-2,3-BDO. The activities of R,R-2,3-butanediol dehydrogenase and diacetyl reductase of the mutant strain were increased by 33% and decreased by 60%, respectively. In addition, it was confirmed that the carbon source depletion of the fermentation broth affects the purity of R,R-2,3-BDO through batch fermentation. Fed-batch fermentation using controlled carbon feeding led to production of 77.3 g/L of R,R-2,3-BDO with high optical purity (> 99% of C4 products) at 48 h. Additionally, fed-batch culture using corn steep liquor as an alternative nitrogen source led to production of 70.3 g/L of R,R-2,3-BDO at 60 h. The fed-batch fermentation broth of P. polymyxa MDBDO, which contained highly pure R,R-2,3-BDO, significantly stimulated the growth of soybean and strawberry seedlings. Conclusions This study suggests that P. polymyxa MDBDO has potential for use in biological plant growth promoting agent applications. In addition, our fermentation strategy demonstrated that high-purity R,R-2,3-BDO can be produced at high concentrations using P. polymyxa.

Rebaudioside A was modified via glucosylation by recombinant dextransucrase of Leuconostoc lactis EG001 in Escherichia coli BL21 (DE3), forming single O‐α‐D‐glucosyl‐(1″→6′) rebaudioside A with yield of 86%. O‐α‐D‐glucosyl‐(1″→6′) rebaudioside A was purified using HPLC and Diaion HP‐20 and its properties were characterized for possible use as a food ingredient. Almost 98% of O‐α‐D‐glucosyl‐(1″→6′) rebaudioside A was dissolved after 15 days of storage at room temperature, compared to only 11% for rebaudioside A. Compared to rebaudioside A, O‐α‐D‐glucosyl‐(1″→6′) rebaudioside A showed similar or improved acidic or thermal stability in commercial drinks. Thus, O‐α‐D‐glucosyl‐(1″→6′) rebaudioside A could be used as a highly pure and improved sweetener with high stability in commercial drinks. Practical Application The proposed method can be used to generate glucosyl rebaudioside A by enzymatic glucosylation. Simple glucosyl rebaudioside A exhibited high acid/thermal stability and improved sweetener in commercialized drinks. This method can be applied to obtain high value‐added bioactive compounds by enzymatic modification.