For a long time, the genus Bacillus has been known and considered among the most applicable genera in several fields. Recent taxonomical developments resulted in the identification of more species in Bacillus-related genera, particularly in the order Bacillales (earlier heterotypic synonym: Caryophanales), with potential application for biotechnological and industrial purposes such as biofuels, bioactive agents, biopolymers, and enzymes. Therefore, a thorough understanding of the taxonomy, growth requirements and physiology, genomics, and metabolic pathways in the highly diverse bacterial order, Bacillales, will facilitate a more robust designing and sustainable production of strain lines relevant to a circular economy. This paper is focused principally on less-known genera and their potential in the order Bacillales for promising applications in the industry and addresses the taxonomical complexities of this order. Moreover, it emphasizes the biotechnological usage of some engineered strains of the order Bacillales. The elucidation of novel taxa, their metabolic pathways, and growth conditions would make it possible to drive industrial processes toward an upgraded functionality based on the microbial nature.

A crude-oil-degrading, Gram-stain-positive actinobacterial strain, RIPIT, was isolated from a soil sample collected from an oil-contaminated mud pit in Khangiran oil and gas field, in the north-east of Iran. RIPIT was strictly aerobic, catalase- and oxidase-positive. The strain grew with 0–12.5 % (w/v) NaCl (optimum 3–5 %), at 25–55 °C (optimum 45 °C) and at pH 6.0–9.5 (optimum pH 7.0). The results of 16S rRNA gene sequence comparative analysis indicated that RIPIT represents a member of the genus Prauserella , with high phylogenetic similarity to Prauserella coralliicola SCSIO 11529T (97.5 %), Prauserella endophytica SP28S-3T (97.5 %) and Prauserella marina MS498T (97.2 %). DNA–DNA relatedness values between the novel strain and P. coralliicola DSM 45821T, P. endophytica DSM 46655T and P. marina DSM 45268T were 28 , 19 and 23 %, respectively. The cell wall peptidoglycan of RIPIT contained meso-diaminopimelic acid as the diamino acid and the whole-cell sugars are galactose and arabinose. The polar lipids pattern contained phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol and two unknown phospholipids. Its cellular fatty acids pattern consisted of C17 : 1ω6c, iso-C16 : 0 and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH), and the major respiratory quinone was MK-9(H4). The G+C content of the genomic DNA was 69 mol%. On the basis of polyphasic taxonomic data we propose that RIPIT represents a novel species of the genus Prauserella , for which the name Prauserella oleivorans sp. nov. is proposed. The type strain of Prauserella oleivorans is RIPIT (=IBRC-M 10906T=LMG 28389T).

We carried out a polyphasic taxonomic study on a new halophilic strain designated 3(2)^T, isolated from Meighan wetland, Iran. Cells of the novel strain were Gram-stain-negative, non-hemolytic, catalase- and oxidase-positive, rod-shaped, non-endospore-forming and motile. Cell growth occurred at 3–15 % NaCl (w/v; optimum, 5 %), pH 7.0–9.0 (optimum, pH 7.5–8.0) and 15–35 °C (optimum, 30 °C). 16S rRNA gene sequence comparisons confirmed the affiliation of strain 3(2)^T to the class Gammaproteobacteria and the genus Halomonas with highest similarity to Halomonas daqiaonensis YCSA28^T (98.4 %) and Halomonas ventosae Al12^T (97.9 %). Experimental and in silico DNA–DNA hybridization values were 42.7 and 35.1% with H. daqiaonensis IBRC-M 10931^T and 48 and 35.2% with H. ventosae IBRC-M 10566^T, respectively, and indicated that they are different members of the same genus. The genome of the type strain was characterized by a size of 3.83 Mbp with 63 scaffolds and a G+C content of 64.8 mol%. Moreover, the average nucleotide identity values against H. ventosae Al12^T and H. daqiaonensis YCSA28^T were 88.8 and 88.5 %, respectively. The predominant respiratory quinone was Q-9 (92 %) with Q-8 (8 %) as a minor component. Major fatty acids were C_16 : 0 cyclo, C_19 : 0 ω8c, C_16 : 1 ω7c and/or iso-C_15:0 2-OH, C_12 : 0 3-OH and C_18 : 1 ω7c. The polar lipid profile of the strain contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphoaminoglycolipid and four unidentified phospholipids. According to our results, strain 3(2)^T could be classified as a novel species in the genus Halomonas for which the name Halomonas lysinitropha sp. nov. is proposed. The type strain is 3(2)^T (=IBRC M 10929^T=LMG 29450^T=CIP 111708^T).