One-carbon (C1) chemicals are potential building blocks for cheap and sustainable re-sources such as methane, methanol, formaldehyde, formate, carbon monoxide, and more. These resources have the potential to be made into raw materials for various products used in our daily life or precursors for pharmaceuticals through biological and chemical processes. Among the soluble C1 substrates, methanol is regarded as a biorenewable platform feedstock because nearly all bioresources can be converted into methanol through syngas. Synthetic methylotrophy can be exploited to produce fuels and chemicals using methanol as a feedstock that integrates natural or artificial methanol assimilation pathways in platform microorganisms. In the methanol utilization in methylotrophy, methanol dehydrogenase (Mdh) is a primary enzyme that converts methanol to formaldehyde. The discovery of new Mdhs and engineering of present Mdhs have been attempted to develop synthetic methylotrophic bacteria. In this review, we describe Mdhs, including in terms of their enzyme properties and engineering for desired activity. In addition, we specifically focus on the application of various Mdhs for synthetic methylotrophy.

Sweet potato is the 11th most important food crop in the world and an excellent source of nutrition. Postharvest diseases were monitored in sweet potato storage roots collected from the local markets in Korea during 2021. Several diseases including Fusarium surface and root rot, charcoal rot, dry rot, and soft rot were observed in the postharvest sweet potatoes. A total of 68 fungal isolates were obtained from the diseased samples, and the isolates were grouped into 8 different fungal colony types. Based on multilocus phylogeny and morphological analysis of 17 representative isolates, the isolates were identified as Fusarium oxysporum, F. ipomoeae, F. solani, Penicillium citrinum, P. rotoruae, Aspergillus wentii, Mucor variicolumellatus (Mu. circinelloides species complex), and Macrophomina phaseolina. F. oxysporum was the predominant pathogen as this is the most common pathogen of sweet potato storage roots causing the surface rot disease, and M. phaseolina caused the most severe disease among the pathogens. Dual culture antagonistic assays were evaluated using Trichoderma harzianum strains CMML20–26 and CMML20–27. The results revealed that the two strains showed strong antifungal activity in different ranges against all tested pathogens. This study provides an understanding of diverse postharvest diseases in sweet potatoes and suggests potential biocontrol agents to manage the diseases. In addition, this is the first report of sweet potato storage root rot diseases caused by A. wentii, and P. rotoruae worldwide.

Sweet potato (Ipomoea batatas) production is threatened by fungal diseases like Fusarium wilt and black rot, causing yield losses. Remedies like fungicides pose environmental and health risks, prompting the need for sustainable biocontrol solutions. In this study, an endophytic bacterium strain CMML21-49 isolated from sweet potato roots in Naju-si, Korea exhibited strong in vitro antifungal activity against Fusarium oxysporum, Ceratocystis fimbriata, Sclerotinia sclerotiorum, and Rhizoctonia solani. Based on 16S rRNA and gyrB gene sequencing, the strain CMML21-49 was identified as Bacillus velezensis. Lipopeptides (bacillomycin D, fengycin A, surfactin A) were identified by UPLC-QTOF-MS and these crude lipopeptides drove the antifungal effects, achieving strong inhibition of F. oxysporum and C. fimbriata. Optimized culture conditions yielded 0.93 g/L lipopeptides, scaled to 0.96 g/L in a 1.5 kL fermenter, and a spray-dried formulation maintained high viability (6.4–8.9 × 1010 CFU/g) over six weeks at 4–54℃. Application of CMML21-49 reduced F. oxysporum and C. fimbriata diseased areas in storage root assays and showed 61.54% and 53.85% control efficiencies against Fusarium wilt and black rot, respectively, in field trials. Additionally, postharvest assays achieved over 50% disease reduction by treatment of the strain. This study presents optimized large scale culture conditions for the B. velezensis strain as well as excellent storage stability and suitability for long-term transport and on-farm use. The findings highlight the B. velezensis strain as a promising and sustainable biocontrol agent, offering a scalable, eco-friendly biocontrol solution for sweet potato fungal diseases.

Manures from livestock industries and farmyards should be managed for land application. Currently, a deep pit or barn system is adopted by many swine farms for manure management, therefore releasing harmful gases and rising the total global emissions of GHGs. This research focuses on the effectiveness of the brown seaweed Sargassum horneri as a masking agent to mitigate odor-generating gaseous pollutants and reduce the emissions of volatile fatty acids (VFAs) from swine manure storage facilities. Using an optimized procedure, we compared the gaseous emissions from two manure storage barns, one containing swine manure masked with S. horneri and the other without masking as a control, over a 30-day period. The results showed that, compared to the control, seaweed masking significantly reduced the sulfide and VFA contents. Furthermore, reductions of 99.48% in H₂S, 60 ± 5.21% in NH₃ and 74.28 ± 2.14% in gaseous amine emissions were observed within the experimental period. Intriguingly, seaweed masking had beneficial effects, decreasing the total odor content by 97.78 ± 3.15% and increasing the nutrient quality of the manure. S. horneri has great potential as a masking agent in swine manure management to control environmental pollution.

The beach vitex (Vitex rotundifolia L.), a member of the Lamiaceae family, is a salt-tolerant, woody perennial common in coastal areas worldwide. Plant–fungal association was monitored in the shoreline forest area of Wando Island in Korea in 2020, and leaf samples showing leaf spot disease were collected. Eight fungal isolates were recovered from the samples on PDA and identified based on the morphological characteristics and multilocus molecular phylogeny. Among the eight isolates, four were identified as Alternaria alternata, two as Fusarium humuli, one as Colletotrichum aenigma, and one as Stagonosporopsis caricae. Pathogenicity tests of the fungal isolates on the detached leaves of beach vitex revealed that S. caricae CMML20–2 and A. alternata (CMML20–7, CMML20–8, CMML20–9, and CMML20–10) caused disease lesions while the other species did not. The fungal species S. caricae, C. aenigma, and F. humuli are the first reported in the host worldwide, and S. caricae and F. humuli are first reported in Korea. In vitro fungicide sensitivity assays were carried out based on a measurement of diametrical mycelial growth on media amended with different doses of the fungicides fludioxonil, metconazole, and fluxapyroxad. Fungicide sensitivity varied significantly among the species, and the A. alternata and S. caricae isolates were more sensitive to fluxapyroxad than the other isolates. Our study contributes to the understanding of fungal diversity in forest mycology and demonstrates that pathogenic fungi including A. alternata and S. caricae might accelerate decline in leaf health.